Exam 3: Producing Data

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?

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?

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.

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?

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?

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?

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"?

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?

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?

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 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

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 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 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?

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?

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?

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?

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?

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 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?