Deck 3: Producing Data

Question 1

Which method will tend to give better statistical results?

A)Observational studies
B)Experiments
C)Neither
D)Observational studies and experiments will likely give the same results

Answer 1

Experiments

Question 2

I am interested in finding out how much time the typical college student spends on Facebook.How should I collect my data?

A)Select a sample from the population of college students.
B)Select a population from the sample of college students.
C)Conduct a census of all college students.
D)None of the above

Answer 2

Select a sample from the population of college students.

Question 3

Many people are fearful of flying with certain airline carriers if the carrier has experienced a major crash in the past.This decision not to fly on certain airlines solely because of a single crash history is an example of ________.

A)available data
B)statistical inference
C)anecdotal evidence
D)exploratory data analysis

Answer 3

anecdotal evidence

Question 4

What do you call experimental units that are human beings?

A)Population
B)Samples
C)Subjects
D)Experiments

Question 5

In order to determine if smoking causes cancer,researchers surveyed a large sample of adults.For each adult they recorded whether the person had smoked regularly at any period in their life and whether the person had cancer.They then compared the proportion of cancer cases in those who had smoked regularly at some time in their lives with the proportion of cases in those who had never smoked regularly at any point in their lives.The researchers found a higher proportion of cancer cases among those who had smoked regularly than among those who had never smoked regularly.What type of study is this?

A)An observational study that is a sample survey
B)An observational study that is not a sample survey
C)An experiment but not a double-blind experiment
D)A double-blind experiment
E)A block design

Question 6

Bob has a severe cold.His roommate takes a garlic tablet every morning and has not had a cold in 2 years.Bob's aunt also has a friend who takes garlic tablets daily and has not had a cold in more than a year.Based on these data,Bob decides to start taking garlic tablets as soon as his cold clears up.What type of study is Bob's decision based on?

A)Anecdotal evidence
B)An observational study based on available data
C)An observational study that is a sample survey
D)An experiment

Question 7

Matched pairs is a common form of blocking that can be used to compare three or more treatments.

Question 8

Twenty students in an introductory psychology class were selected by random sampling and asked to participate in an experiment to determine the effects of sunlight on sleeping patterns.What is the experimental unit/subject?

A)The 20 students
B)The entire psychology class
C)The sunlight
D)Different sleeping patterns

Question 9

A market research company wishes to find out which of two Internet search engines the population of students at a university prefers to use: Google or MSN Search.A random sample of students is selected,and each one is asked to search for a certain subject using Google and then MSN,or vice versa.The order of the two searches was determined at random.They then indicated which Internet search engine they preferred.What type of study is this?

A)An observational study that is not a sample survey
B)An observational study that is a sample survey
C)An experiment but not a double-blind experiment
D)A double-blind experiment
E)None of the above

Question 10

An experiment that favors a certain outcome over other outcomes is called ______.

A)favored
B)systematic
C)confounded
D)biased

Question 11

Sickle-cell disease is a painful disorder of the red blood cells that in the United States affects mostly African Americans.To investigate whether the drug hydroxyurea can reduce the pain associated with sickle-cell disease,a study by the National Institutes of Health gave the drug to 150 sickle-cell sufferers and a placebo to another 150 sufferers.The researchers then counted the number of episodes of pain reported by each subject.What is the response variable in this study?

A)The drug hydroxyurea
B)The number of episodes of pain
C)The presence of sickle-cell disease
D)The number of red blood cells

Question 12

The first day of class your statistics professor collects information about you,such as your age,your hometown,your commute time,and whether you are working a part-time job.Later for a class project you decide to use this data to find out information about your class.This is an example of using ________.

A)available data
B)anecdotal evidence
C)extrapolation
D)confounding

Question 13

In order to assess the effects of exercise on reducing cholesterol,a researcher sampled 50 people from a local gym who exercised regularly and 50 people from the surrounding community,who,it was assumed,did not exercise regularly.Each subject reported to a clinic to have their cholesterol measured.The subjects were unaware of the purpose of the study,and the technician measuring the cholesterol was not aware of whether the subjects exercised regularly or not.What type of study is this?

A)An observational study that is a sample survey
B)An observational study that is not a sample survey
C)An experiment but not a double-blind experiment
D)A double-blind experiment
E)A matched pairs experiment

Question 14

A study is designed to determine whether grades in a statistics course could be improved by offering special review material.The 250 students enrolled in a large introductory statistics class are also enrolled in one of 20 lab sections.The 20 lab sections are randomly divided into two groups of 10 lab sections each.The students in the first set of 10 lab sections are given extra review material during the last 15 minutes of each weekly lab session.The students in the remaining 10 lab sections receive the regular lesson material,without the extra review material.The grades of the students who reviewed weekly were higher,on average,than the students who did not review every week.What type of study is this?

A)An observational study that is a sample survey
B)An observational study that is not a sample survey
C)An experiment but not a double-blind experiment
D)A double-blind experiment
E)A matched pairs experiment

Question 15

A baseball enthusiast believes pitchers who strike out a lot of batters also walk a lot of batters.He reached this conclusion by going to the library and examining the records of all major league pitchers between 1990 and 1995.What type of study is his decision based on?

A)Anecdotal evidence
B)An observational study based on available data
C)An observational study based on a sample survey
D)An experiment

Question 16

Which of the following statements best describes the difference between an observational study and an experiment?

A)In an experiment the researcher is careful to determine exactly what is to be observed,whereas in an observational study there is greater concern about how the observations are made.
B)In an experiment the data are obtained using careful controls on the treatments,but in an observational study the data are obtained through careful observation of the responses.
C)In an experiment treatments are deliberately imposed upon individuals and their responses are observed.However,in an observational study without any attempt to influence the responses,individuals are observed and variables of interest are measured.
D)There are really no significant differences between observational studies and experiments.They are different names for essentially the same type of study.
E)Without concrete examples,it is not possible to detect what the differences might be.

Question 17

An experiment was conducted and the results involving the effect of a particular experimental variable were widely reported.Later,a critic commented that,in fact,nothing could be usefully learned from the study because the observed effect was confounded.What did the critic mean by this?

A)The experimenter really wasn't clear about what was desired,so the experiment was not well defined.
B)The results were so badly described that the critic could not figure out exactly what was being concluded.
C)The critic felt there was confusion as to whether or not the study was an observational study or a real experiment.
D)Because of the way the experiment was conducted,the effect observed in the experiment,ascribed to a particular variable,was mixed up with other influences.
E)Without knowing more about the experiment,we can't know exactly what the critic meant by this.

Question 18

What is the best way to control for lurking variables?

A)Compare two or more treatments.
B)Randomize to assign experimental units to treatments.
C)Repeat each treatment on many units.
D)None of the above

Question 19

Seventy-five college students took part in a study initiated by a large computer manufacturer.The company is designing a new type of laptop computer and has created prototypes of it with two different keyboard designs.They are also including the current design of the laptop in the experiment.Each of the students was randomly assigned to one of the three types of computers.The students were asked to spend 15 minutes on one of the computers,performing several tasks (typing words,numbers,making corrections,etc. ).The ease of use of the keyboard was then rated on a five-point scale by having the students fill out a short questionnaire.Which of the following basic principles of statistical design was not used in this experiment?

A)Control
B)Randomization
C)Repetition
D)Blinding

Question 20

An experiment is conducted to examine the effects of a certain drug on rats.A pair of rats is housed in a cage.Suppose that the drug is to be given by injection.One drug treatment is assigned to one of the rats in a cage,while the other drug is assigned to the other rat.What is the experimental unit/subject?

A)The cage
B)The rats
C)The drug
D)None of the above

Question 21

A medicine to remove the redness in eyes was tested in a group of 100 students.Each student took either the medicine or a placebo in both eyes.The specific treatment for each student was decided by flipping a coin.The participants in the study did not know if heads or tails resulted in the medication.The participants were given some free time after receiving their drops.The researcher did not keep track of what they did in that free time.It turns out that many of the people receiving the medicine spent their time outside and many of the people receiving the placebo spent their time inside.The results could now be biased because the variable location (inside versus outside)is an example of a ___________ variable.

A)lurking
B)confounding
C)response
D)control

Question 22

A group of college students believes that herbal tea has remarkable restorative powers.To test its theory,the group makes weekly visits to a local nursing home,visiting with residents,talking with them,and serving them herbal tea.After several months many of the residents are more cheerful and healthy.What is the explanatory variable in this experiment?

A)The emotional state of the residents
B)Herbal tea
C)The fact that this is a local nursing home
D)The college students

Question 23

A researcher is studying the relationship between sugar consumption and weight gain.Twelve volunteers were randomly assigned to one of two groups.The first group of five participants was put on a diet low in sugar and the second group of the remaining seven participants received 10% of their calories from sugar.After 8 weeks,weight gain was recorded from each participant.Which of the following basic principles of statistical design was not used in this experiment?

A)Control
B)Randomization
C)Repetition
D)Blinding

Question 24

A group of college students believes that herbal tea has remarkable restorative powers.To test its theory,the group makes weekly visits to a local nursing home,visiting with residents,talking with them,and serving them herbal tea.After several months many of the residents are more cheerful and healthy.What is the lurking variable in this experiment?

A)The emotional state of the residents
B)Herbal tea
C)The fact that this is a local nursing home
D)Visits of the college students

Question 25

Twelve people,who suffer from chronic fatigue syndrome,volunteer to take part in an experiment to see if shark fin extract will increase one's energy level.Eight of the volunteers are men and four are women.Half of the volunteers are to be given shark fin extract twice a day and the other half a placebo twice a day.We wish to make sure that four men and two women are assigned to each of the treatments,so we decide to use a block design with the men forming one block and the women the other.Each of the eight men receives a label: 1 through 8.Use the list of random digits below to determine the labels of the four men who are to be given shark fin extract twice a day.Start at the beginning of the list and use single-digit labels.

A)0,2,9,0
B)0,2,9,8
C)2,8,4,6
D)2,9,8,4

Question 26

The head of the quality control department at a publishing company is studying the effects of the type of glue and the type of binding on the strength of the bookbinding.The company has three possible glues to choose from and the book can either be bound as a paperback or a hardback.What is/are the factor(s)in this study?

A)The strength of the bookbinding
B)The type of glue and the type of binding
C)The three possible glues
D)Paperback versus hardback

Question 27

In a recent study,a random sample of children in grades 2 through 4 showed a significant negative relationship between the amount of homework assigned and student attitudes.What type of study is this?

A)An experiment
B)An observational study that is not a sample survey
C)An observational study that is a sample survey
D)The establishing of a causal relationship through correlation
E)A block design,with grades as blocks

Question 28

Twelve people,who suffer from chronic fatigue syndrome,volunteer to take part in an experiment to see if shark fin extract will increase one's energy level.Eight of the volunteers are men and four are women.Half of the volunteers are to be given shark fin extract twice a day and the other half a placebo twice a day.We wish to make sure that four men and two women are assigned to each of the treatments,so we decide to use a block design with the men forming one block and the women the other.Suppose one of the researchers is responsible for measuring if a subject displays an increase in energy level.What design principle should be added to this experiment?

A)Use two placebos.
B)Use a stratified sampling design to assign subjects to treatments.
C)Use fewer subjects but observe them more frequently.
D)Conduct the study as a double-blind experiment.

Question 29

One hundred volunteers who suffer from severe depression are available for a study.Fifty are selected at random and are given a new drug that is thought to be particularly effective in treating severe depression.The other 50 are given an existing drug for treating severe depression.A psychiatrist evaluates the symptoms of all volunteers after 4 weeks in order to determine if there has been substantial improvement in the severity of the depression.In which situation would this study be double blind?

A)If neither drug had any identifying marks on it
B)If all volunteers were not allowed to see the psychiatrist nor was the psychiatrist allowed to see the volunteers during the session when the psychiatrist evaluated the severity of the depression
C)If neither the volunteers nor the psychiatrist knew which treatment any person had received
D)All of the above

Question 30

In a recent study,a random sample of children in grades 2 through 4 showed a significant negative relationship between the amount of homework assigned and student attitudes.What type of variable is the amount of homework assigned?

A)An explanatory variable
B)A response variable
C)A confounding variable
D)A lurking variable

Question 31

A researcher is studying the relationship between sugar consumption and weight gain.Twelve volunteers were randomly assigned to one of two groups.The first group of five participants was put on a diet low in sugar and the second group of the remaining seven participants received 10% of their calories from sugar.After 8 weeks,weight gain was recorded from each participant.Each of the 12 volunteers receives a label: 01 through 12.Use the list of random digits below to determine the labels of the first five participants selected who were put on a low-sugar diet.Start at the beginning of the list and use double-digit labels.

A)8,1,5,0,7
B)8,1,5,7,2
C)2,6,10,9,12
D)2,2,6,10,9

Question 32

Twelve people,who suffer from chronic fatigue syndrome,volunteer to take part in an experiment to see if shark fin extract will increase one's energy level.Eight of the volunteers are men and four are women.Half of the volunteers are to be given shark fin extract twice a day and the other half a placebo twice a day.We wish to make sure that four men and two women are assigned to each of the treatments,so we decide to use a block design with the men forming one block and the women the other.For which reason is a block design appropriate in this experiment?

A)Gender equity is an important legal consideration in this study.
B)We believe men and women will respond differently to treatments.
C)We want the conclusions to apply equally to men and women.
D)All of the above

Question 33

One hundred volunteers who suffer from severe depression are available for a study.Fifty are selected at random and are given a new drug that is thought to be particularly effective in treating severe depression.The other 50 are given an existing drug for treating severe depression.A psychiatrist evaluates the symptoms of all volunteers after 4 weeks in order to determine if there has been substantial improvement in the severity of the depression.What is the explanatory variable or factor in this study?

A)Which drug the volunteers receive
B)The use of randomization and the fact that this was a comparative study
C)The extent to which the depression was reduced
D)The use of a psychiatrist to evaluate the severity of depression

Question 34

An amateur gardener decides to change the variety of tomatoes for this year to see if the yield improves.He put in six plants the previous year and six plants this year,using the same part of the garden.The average yield per plant was 11.3 pounds per plant in the previous year and 14.5 pounds per plant using the new variety.What is this an example of?

A)An experiment
B)An observational study not an experiment
C)The elimination of all confounding variables by design,because the gardener used the same part of the garden in both years
D)A multistage design,because 2 years were involved

Question 35

A study to determine whether or not a football filled with helium traveled farther when kicked than one filled with air found that the football filled with helium went,on average,farther than the one filled with air.However,the difference was not statistically significant.What is the response variable in this study?

A)The air or helium with which the football was filled
B)The number of kickers
C)The distance that the football traveled
D)There is no response because the difference was not statistically significant.

Question 36

Researchers wished to determine if a new experimental medication will reduce the symptoms of allergy sufferers without the side effect of drowsiness.To investigate this question,the researchers gave the new medication to 50 adult volunteers who suffer from allergies.Forty-four of these volunteers reported a significant reduction in their allergy symptoms without any drowsiness.What are the experimental units in this study?

A)The researchers
B)The 50 adult volunteers
C)The 44 volunteers who reported a significant reduction in their allergy symptoms without any drowsiness
D)The six volunteers who did not report a significant reduction in their allergy symptoms without any drowsiness

Question 37

One hundred volunteers who suffer from severe depression are available for a study.Fifty are selected at random and are given a new drug that is thought to be particularly effective in treating severe depression.The other 50 are given an existing drug for treating severe depression.A psychiatrist evaluates the symptoms of all volunteers after 4 weeks in order to determine if there has been substantial improvement in the severity of the depression.Suppose volunteers were first divided by gender,and then half of the men were randomly assigned to the new drug and half of the women were assigned to the new drug.The remaining volunteers received the other drug.What is this an example of?

A)Replication
B)Confounding-the effects of gender will be mixed up with the effects of the drugs.
C)A block design
D)A matched pairs design

Question 38

A researcher is studying the relationship between sugar consumption and weight gain.Twelve volunteers were randomly assigned to one of two groups.The first group of five participants was put on a diet low in sugar and the second group of the remaining seven participants received 10% of their calories from sugar.After 8 weeks,weight gain was recorded from each participant.What type of study is this?

A)An observational study that is a sample survey
B)An observational study that is not a sample survey
C)An experiment but not a double-blind experiment
D)A double-blind experiment
E)A matched pairs experiment

Question 39

Will a fluoride mouthwash used after brushing reduce cavities? Twenty sets of twins were used to investigate this question.One member of each set of twins used the mouthwash after each brushing,the other did not.After 6 months,the difference in the number of cavities of those using the mouthwash was compared with the number of cavities of those who did not use the mouthwash.This experiment uses _________.

A)random placebos
B)double blinding
C)double replication
D)a matched pairs design

Question 40

Researchers wished to determine if a new experimental medication will reduce the symptoms of allergy sufferers without the side effect of drowsiness.To investigate this question,the researchers gave the new medication to 50 adult volunteers who suffer from allergies.Forty-four of these volunteers reported a significant reduction in their allergy symptoms without any drowsiness.How could this study be improved?

A)Include people who do not suffer from allergies in the study in order to represent a more diverse population.
B)Repeat the study with only the 44 volunteers who reported a significant reduction in their allergy symptoms without any drowsiness,giving them a higher dosage this time.
C)Give the spouses of the volunteers a placebo.
D)Use randomization to divide the volunteers into 2 groups-one to receive the experimental medication and one to receive the placebo.

Question 41

To investigate whether or not sending text messages while driving impacts driving ability,we had 100 participants (50 men and 50 women)drive an obstacle course under one of the following conditions: 1)no texting while driving,2)sending five text messages while driving,or 3)sending 10 text messages while driving.We measured the accuracy with which the subjects drove the obstacle course from a scale of 1 to 10 (1 = poor and 10 = excellent).What is the treatment in this study?

Question 42

A study was conducted with the objective of determining the effect of two different strength-training programs,one involving the use of a balance ball and the other using stationary exercise equipment,on blood pressure and cholesterol levels in women over the age of 60.Eighty women over the age of 60 were identified and randomly divided into two equal-sized experimental groups.Each member of the two groups was trained and allowed to follow the prescribed routine for 8 weeks.The subjects were aware of the purpose of the study but not that there were two different treatment groups involved.The cholesterol levels and blood pressure for subjects were measured at the start and at the end of the 8 weeks.The experimenter and the medical technician were not told to which group any of the subjects were assigned.This is an example of an attempt to conduct a

A)matched pairs design.
B)design involving blocking.
C)designed experiment that failed because it had systematic bias.
D)double-blind randomized experiment.
E)randomized experiment with two factors: type of exercise and type of medical measurement.

Question 43

A local research firm often uses newspaper advertisements to invite individuals to volunteer for various experiments the firm is planning to conduct.One such study was to determine if a newly formulated cream had any beneficial effect on individuals suffering with psoriasis.Psoriasis sufferers were invited to participate in a study with volunteers to be given either the new cream or a placebo in the form of a cream with the similar appearance and feel as the new cream.What conclusions can be drawn from such studies involving volunteers?

A)Because there is bias associated with the selection of subjects,nothing can be concluded.
B)In such a study there is great potential for the presence of confounding or lurking variables,so little information can be gained.
C)If one believes the subjects form a representative sample from the population,useful information will be gained from such studies.
D)Because there is no control over the selection of subjects,little will be learned from such studies.
E)Useful information will be gained from studies such as this provided that the individuals who volunteer are randomly assigned to either receive the experimental treatment or the placebo.

Question 44

The head of the quality control department at a publishing company is studying the effects of the type of glue and the type of binding on the strength of the bookbinding.The company has three possible glues to choose from and the book can either be bound as a paperback or a hardback.What should the company do if repetition is to be part of this study?

A)The company should perform the study today and again tomorrow,and preferably again the day after that.
B)The company should apply the glue to the binding,wait for 5 minutes,and then apply it again before binding the book completely.
C)The company should use multiple books of the same binding type for each of the three types of glue.
D)None of the above

Question 45

Following the analysis of a well-designed,completely randomized experiment,it was reported that the observed effect was statistically significant.Which of the following statements best explains the meaning of the phrase "statistically significant"?

A)The observed result made sense to the experimenter since it was what was hoped would happen.
B)The observed effect happened because the experiment was properly designed and carried out without bias.
C)The experimenter carefully employed the basic principles of experimental design in conducting the study.
D)The laws of probability say that this observed result would be expected to happen by chance.
E)The observed effect was sufficiently large so that it would rarely occur simply by chance.

Question 46

To investigate whether or not sending text messages while driving impacts driving ability,we had 100 participants (50 men and 50 women)drive an obstacle course under one of the following conditions: 1)no texting while driving,2)sending five text messages while driving,or 3)sending 10 text messages while driving.We measured the accuracy with which the subjects drove the obstacle course from a scale of 1 to 10 (1 = poor and 10 = excellent).Why is a control necessary in this experiment?

A)The control is used for the subjects who do not know how to send text messages.
B)The control helps determine if men are better drivers than women.
C)The control helps control for the lurking variables.

Question 47

The head of the quality control department at a publishing company is studying the effects of the type of glue and the type of binding on the strength of the bookbinding.The company has three possible glues to choose from and the book can either be bound as a paperback or a hardback.How many treatments is the company considering?

A)2
B)3
C)5
D)6

Question 48

The three basic principles of statistical design of experiments are

A)control,comparison,and confounding.
B)control,randomization,and repetition.
C)blocking,blinding,and bias avoidance.
D)randomization,control,and pairing.
E)comparison,blocking,and pairing.

Question 49

The head of the quality control department at a publishing company is studying the effects of the type of glue and the type of binding on the strength of the bookbinding.The company has three possible glues to choose from and the book can either be bound as a paperback or a hardback.Many stacks of books are ready to be bound-some in paperback form,some in hardback form.As part of this study,45 books are to be randomly selected from each type of binding and then randomly assigned to one of the three types of glue.What type of sampling method is being used to select the books?

A)Simple random sample
B)Stratified sample
C)Multistage sample
D)None of the above

Question 50

A study was conducted to determine the effect of weather on varieties of corn grown for grazing by cattle in Alberta,Canada.To conduct the study,five varieties of corn were considered (one grazing,one short-stature,and three conventional)with harvesting of crops conducted on four occasions (two dates in September,one in December,and one in January).The experimental treatments were assigned at random to plots of land at each of two different locations in Alberta in order to control for natural variations in location.The crude protein concentration of the harvested corn was determined. The two Alberta locations used in the study were Lacombe and Brooks.In this study location is considered to be what kind of variable?

A)A factor variable
B)A treatment variable
C)A blocking variable
D)A lurking variable
E)A control variable

Question 51

Suppose you want to determine if there are differences in the average prices among items at three local supermarket chains.What type of study would work best?

A)An observational study
B)An experiment
C)None of the above

Question 52

To investigate whether or not sending text messages while driving impacts driving ability,we had 100 participants (50 men and 50 women)drive an obstacle course under one of the following conditions: 1)no texting while driving,2)sending five text messages while driving,or 3)sending 10 text messages while driving.We measured the accuracy with which the subjects drove the obstacle course from a scale of 1 to 10 (1 = poor and 10 = excellent).We are testing the effect of sending text messages at three different _____.

A)treatments
B)levels
C)factors
D)None of the above

Question 53

To investigate whether or not sending text messages while driving impacts driving ability,we had 100 participants (50 men and 50 women)drive an obstacle course under one of the following conditions: 1)no texting while driving,2)sending five text messages while driving,or 3)sending 10 text messages while driving.We measured the accuracy with which the subjects drove the obstacle course from a scale of 1 to 10 (1 = poor and 10 = excellent).What is the response variable in this study?

Question 54

To investigate whether or not sending text messages while driving impacts driving ability,we had 100 participants (50 men and 50 women)drive an obstacle course under one of the following conditions: 1)no texting while driving,2)sending five text messages while driving,or 3)sending 10 text messages while driving.We measured the accuracy with which the subjects drove the obstacle course from a scale of 1 to 10 (1 = poor and 10 = excellent).What is a possible lurking variable in this experiment?

A)The driving skill level of participants and the skill level at sending text messages
B)The number of text messages sent while driving
C)The men and women in the study

Question 55

To investigate whether or not sending text messages while driving impacts driving ability,we had 100 participants (50 men and 50 women)drive an obstacle course under one of the following conditions: 1)no texting while driving,2)sending five text messages while driving,or 3)sending 10 text messages while driving.We measured the accuracy with which the subjects drove the obstacle course from a scale of 1 to 10 (1 = poor and 10 = excellent).Explain how you would randomize this study.

Question 56

A new drug has recently become available which,it is claimed,will relieve the symptoms of restless leg syndrome (RLS).A physician gave this drug to 30 patients who were known to suffer from RLS.Among these patients,24 reported they experienced some significant relief,though six reported no change.What can be concluded from this information?

A)This study has demonstrated the effectiveness of this new drug against the symptoms of RLS.
B)Nothing much can be concluded since the number of patients in the sample is too small.
C)Care must be taken in reaching any conclusion because there is uncertainty due to the number of patients reporting no effect.
D)Nothing can be concluded since the experiment did not include a control group to compare the results against.
E)Little can be concluded,at least until the experiment is repeated.

Question 57

A study was conducted to determine the effect of weather on varieties of corn grown for grazing by cattle in Alberta,Canada.To conduct the study,five varieties of corn were considered (one grazing,one short-stature,and three conventional)with harvesting of crops conducted on four occasions (two dates in September,one in December,and one in January).The experimental treatments were assigned at random to plots of land at each of two different locations in Alberta in order to control for natural variations in location.The crude protein concentration of the harvested corn was determined. In this experiment the factor(s),number of treatments,and the response are

Question 58

To investigate whether or not sending text messages while driving impacts driving ability,we had 100 participants (50 men and 50 women)drive an obstacle course under one of the following conditions: 1)no texting while driving,2)sending five text messages while driving,or 3)sending 10 text messages while driving.We measured the accuracy with which the subjects drove the obstacle course from a scale of 1 to 10 (1 = poor and 10 = excellent).This study includes which of the following?

A)Blinding
B)Control
C)Lack of realism

Question 59

In conducting a randomized comparative experiment,an experimenter will often include a group of subjects,known as a control group,to receive a fake treatment.What is/are the reason(s)such a control group might be included in the experiment?

A)To increase the number of subjects and hence increase the sensitivity of the experiment in detecting effects of the treatment
B)To gain more complete understanding of any biases that might be present in the experiment
C)To enable the experimenter to control the effects of outside variables,such as lurking variables,on the outcome of the experiment
D)To repeat the experiment over a greater number of experimental subjects
E)To enable the experimenter to more easily make a random assignment of subjects to the groups

Question 60

To investigate whether or not sending text messages while driving impacts driving ability,we had 100 participants (50 men and 50 women)drive an obstacle course under one of the following conditions: 1)no texting while driving,2)sending five text messages while driving,or 3)sending 10 text messages while driving.We measured the accuracy with which the subjects drove the obstacle course from a scale of 1 to 10 (1 = poor and 10 = excellent).What type of study is this?

A)An observational study that is a sample survey
B)An observational study that is not a sample survey
C)An experiment
D)A matched pairs study

Question 61

Do people prefer tap or bottled water? For this study pour two water samples into two cups that are the same but marked on the bottom.Each subject then tastes both water samples and rates the taste on a five-point scale (1 = poor to 5 = excellent. )Explain why blocking would or would not be necessary.

Question 62

Suppose you want to determine if there are differences in the average prices among items at three local supermarket chains.Explain why blocking would or would not be necessary in this experiment.

Question 63

Does giving an incentive really work on improving exam scores? For example,consider the following treatments to measure the use of incentives. Treatment 1: No incentive
Treatment 2: Incentive given to all
Treatment 3: Incentive given only if a certain score is received
For this experiment,assume all subjects are seniors at a university.What type of study would work best?

A)An observational study
B)An experiment
C)None of the above

Question 64

Do people prefer tap or bottled water? For this study pour two water samples into two cups that are the same but marked on the bottom.Each subject then tastes both water samples and rates the taste on a five-point scale (1 = poor to 5 = excellent. )Explain why blinding would or would not be necessary.

Question 65

Does giving an incentive really work on improving exam scores? For example,consider the following treatments to measure the use of incentives.
Treatment 1: No incentive
Treatment 2: Incentive given to all
Treatment 3: Incentive given only if a certain score is received
For this experiment,assume all subjects are seniors at a university.Explain why blinding would or would not be necessary in this experiment.

Question 66

Suppose you want to determine if there are differences in the average prices among items at three local supermarket chains.If a block design were used,what would be an appropriate blocking variable for this study?

A)A supermarket
B)A type of item (e.g. ,beverages,medications,condiments,etc. )
C)None of the above

Question 67

Does giving an incentive really work on improving exam scores? For example,consider the following treatments to measure the use of incentives.
Treatment 1: No incentive
Treatment 2: Incentive given to all
Treatment 3: Incentive given only if a certain score is received
For this experiment,assume all subjects are seniors at a university.Explain why blocking would or would not be necessary in this experiment.

Question 68

Do people prefer tap or bottled water? For this study pour two water samples into two cups that are the same but marked on the bottom.Each subject then tastes both water samples and rates the taste on a five-point scale (1 = poor to 5 = excellent. )What type of design is this?

A)Experiment
B)Observational study
C)Matched pairs design
D)Completely randomized design

Question 69

Suppose you want to determine if there are differences in the average prices among items at three local supermarket chains.Explain why blinding would or would not be necessary in this experiment.

Question 70

Does giving an incentive really work on improving exam scores? For example,consider the following treatments to measure the use of incentives. Treatment 1: No incentive
Treatment 2: Incentive given to all
Treatment 3: Incentive given only if a certain score is received
For this experiment,assume all subjects are seniors at a university.If a block design were used,what would be an appropriate blocking variable for this study?

A)Exam
B)Treatment
C)None of the above