Deck 7: Hypothesis Testing With Z Tests

Question 1

What is the percentage of observations that fall between z scores of -1.02 and 0.61?

A) 22.91
B) 34.61
C) 42.48
D) 57.52

Answer 1

57.52

Question 2

The percentile is the:

A) same thing as a percentage.
B) percentage of scores falling at or below a particular raw score.
C) percentage of scores falling at or above a particular raw score.
D) percentage of scores falling between a particular raw score and the mean.

Answer 2

percentage of scores falling at or below a particular raw score.

Question 3

When attempting to find a percentage associated with a z score, the first step involves a _____ to _____ transformation.

A) z score; raw score
B) raw score; z score
C) standard error; z score
D) z score; standard error

Answer 3

raw score; z score

Question 4

In one statistics course, students reported studying an average of 9.92 hours a week, with a standard deviation of 4.54.Treating the class as the population, what is the percentile for a student in the class who studies 11 hours a week? (Round z score to two decimal places.)

A) 9.48
B) 40.52
C) 50.00
D) 59.48

Question 5

In one statistics course, students reported studying an average of 9.92 hours a week, with a standard deviation of 4.54.Jessica is working two jobs and struggles to find time to study, averaging only 3 hours per week.What percent of students are at least as extreme as Jessica, in both directions? (Round z score to two decimal places.)

A) 87.14
B) 43.57
C) 6.43
D) 12.85

Question 6

To determine a person's percentile, first convert the person's _____ score to a z score.

A) normalized
B) raw
C) median
D) formal

Question 7

In one statistics course, students reported studying an average of 9.92 hours a week, with a standard deviation of 4.54.Treating this class as the population, what percent of students study more than 8 hours? (Round z score to two decimal places.)

A) 83.35
B) 66.28
C) 56.84
D) 34.72

Question 8

In one statistics course, students reported studying an average of 9.92 hours a week, with a standard deviation of 4.54.Mark studies 16 hours per week.What percent of students are at least as extreme as Mark, in both directions? (Round z score to two decimal places.)

A) 9.01
B) 10.89
C) 18.02
D) 22.64

Question 9

If the percentage of scores falling between the mean and a z score of 0.30 is 11.79, then what is the percentage of scores falling between the mean and a z score of -0.30?

A) 11.79
B) -11.79
C) 38.21
D) -38.21

Question 10

A z score _____ the mean will always be _____.

A) below; positive
B) above; negative
C) equal to; negative
D) equal to; zero

Question 11

When attempting to find a percentage associated with a z score, the second step involves looking up:

A) a raw score on the raw score table.
B) a standard score on the means table.
C) a z score on the z table.
D) the median to determine skewness.

Question 12

In one statistics course, students reported studying an average of 9.92 hours a week, with a standard deviation of 4.54.Treating this class as the population, what is the percentile for a student in the class who studies 8 hours a week? (Round z score to two decimal places.)

A) 16.28
B) -16.28
C) 33.72
D) -33.72

Question 13

To determine a person's percentile, first convert the person's raw score to a:

A) normalized score.
B) z score.
C) median.
D) formal score.

Question 14

In a raw score to z score transformation, an associated value on the z table provides the percentage of scores:

A) between the mean and the z score.
B) below the mean.
C) above the mean.
D) between the upper and lower limits.

Question 15

A z score _____ the mean will always be _____.

A) below; positive
B) below; negative
C) above; negative
D) equal to; positive

Question 16

If the percentage of scores falling between the mean and a z score of 0.50 is 19.15, then what is the percentage of scores falling below a z score of -0.50?

A) -19.15
B) 19.15
C) 30.85
D) -30.85

Question 17

A z score _____ the mean will always be _____.

A) below; positive
B) above; positive
C) above; negative
D) equal to; positive

Question 18

What proportion of a normal distribution corresponds to z scores less than 1.04?

A) 0.3508
B) 0.1492
C) 0.6492
D) 0.8508

Question 19

In one statistics course, students reported studying an average of 9.92 hours a week, with a standard deviation of 4.54.Treating this class as the population, what percent of students study more than 13 hours a week? (Round z score to two decimal places.)

A) 15.91
B) 24.83
C) 25.17
D) 34.09

Question 20

A single observation can be expressed in a number of ways that all refer to that same observation and the exact same place within the normal curve.These expressions are:

A) formal, informal, and standard.
B) a z score, percentile, and standard score.
C) standard, transformed, and normalized.
D) a raw score, z score, and percentile.

Question 21

Assume the average height for American women is 64 inches with a standard deviation of 2 inches.What percent of groups of size 25 would have mean heights of less than 62 inches? (Round z score to two decimal places.)

A) 50.00
B) 0.40
C) 0.13
D) 0

Question 22

Imagine that the mean height for all Division I women's basketball programs is 69 inches with a standard deviation of 3 inches.The 2010-2011 women's basketball team at the University of Connecticut, with 10 players listed on the roster, had an average height of 71.2 inches.Using the z statistic, what percent of means would fall below that for these UConn Huskies? (Round z score to two decimal places.)

A) 98.98
B) 94.98
C) 86.98
D) 48.98

Question 23

To compare a group mean to a population, compute the:

A) z score.
B) z statistic.
C) mean square error.
D) proportionate reduction in error.

Question 24

A research study that meets all the assumptions of the parametric test used to analyze the data:

A) continues with the performance of the appropriate nonparametric follow-up test.
B) has no bearing on the results of the research study.
C) produces higher quality results than does a research study that fails to meet some of the assumptions.
D) produces lower quality results than does a research study that fails to meet some of the assumptions.

Question 25

_____ requires that all members of a population have an equal chance of being selected for a study.

A) Random selection
B) Random assignment
C) Normal distribution
D) Scale variable assumption

Question 26

To convert a person's percentile rank into a raw score, one needs to know the mean and standard:

A) deviation for the population.
B) error of the sampling distribution.
C) deviation of the sample.
D) error of the population.

Question 27

In one statistics course, students reported studying an average of 9.92 hours a week, with a standard deviation of 4.54.The professor tells David he scored at the 76th percentile.How many hours does he study per week? (Round z score to two decimal places.)

A) 13.14 hours
B) 8.64 hours
C) 12.88 hours
D) 16.24 hours

Question 28

Which statement is NOT an assumption of the z test?

A) The distribution of the population is approximately normal.
B) The distribution of the sample is normal.
C) Participants were randomly selected from the population.
D) The dependent variable is assessed using a scale measure.

Question 29

If a dependent variable is nominal, the assumption that the _____ should not be made.

A) variable is normally distributed
B) variable is assessed using a scale measure
C) participants are randomly selected
D) participants are randomly assigned

Question 30

What are the consequences of failing to meet the assumptions of a parametric test when performing research?

A) If we fail to meet the assumptions of a parametric test, then we will be unable to make any inferences regarding the population.
B) If we fail to meet one assumption of a parametric test, then we cannot perform statistical analysis on the results of the study and will be limited to qualitative descriptions of the data.
C) If we fail to meet even one assumption of a parametric test, then we should perform a nonparametric test instead.
D) If the test is robust to the violation, it does not invalidate the research; however, it may make it more difficult to detect effects.

Question 31

Assume the average height for American women is 64 inches with a standard deviation of 2 inches.What percent of groups of size 25 would have mean heights of more than 64.5 inches? (Round z score to two decimal places.)

A) 10.56
B) 22.82
C) 35.31
D) 89.44

Question 32

Because of the principle of _____, when sample sizes are at least 30, the distribution will most likely resemble a normal distribution.

A) parametric statistics
B) nonparametric statistics
C) the central limit theorem
D) robustness

Question 33

Under what conditions is it permissible to proceed with a hypothesis test even though the assumption that participants are randomly selected is violated?

A) We are cautious about generalizing the results.
B) The sample size is greater than 30.
C) The data are not clearly ratio.
D) The data are not clearly nominal or ordinal.

Question 34

The distribution of means has the same mean as the distribution of scores for the population, and the spread is:

A) Tests
B) Nonparameters
C) Parameters
D) Assumptions

Question 35

Under what conditions is it permissible to proceed with a hypothesis test even though the assumption that the population distribution is approximately normal is violated?

A) We are cautious about generalizing the results.
B) The sample size is greater than 30.
C) The data are not clearly ratio.
D) The data are not clearly nominal or ordinal.

Question 36

Inferential statistical analyses that are NOT based on a set of assumptions about the underlying population are:

A) inaccurate.
B) permissible only when certain assumptions about the sample are met.
C) nonparametric tests.
D) parametric tests.

Question 37

Which statement is NOT an assumption of parametric hypothesis tests?

A) The population is normally distributed.
B) Participants are selected randomly from the population.
C) The dependent variable is assessed using a scale measure.
D) The sample size is greater than 30.

Question 38

In one statistics course, students reported studying an average of 9.92 hours a week, with a standard deviation of 4.54.The professor tells Mackenzie she scored at the 46th percentile.How many hours does she study per week? (Round z score to two decimal places.)

A) 0.10 hours
B) 5.53 hours
C) 9.47 hours
D) 10.37 hours

Question 39

Which statement regarding the denominator of the equation for the z score and that of the z statistic is true?

A) There is no difference between the denominators of the two equations.In both cases, we divide by the standard error.
B) There is no difference between the denominators of the two equations.In both cases, we divide by the standard deviation.
C) When computing a z score, we divide by the population standard deviation, but when computing a z statistic, we divide by the standard error of the sampling distribution.
D) When computing a z statistic, we divide by the population standard deviation, but when computing a z score, we divide by the standard error of the sampling distribution.

Question 40

Under what conditions is the assumption that the dependent variable is assessed on a scale measure NOT met?

A) We are cautious about generalizing the results.
B) The sample size is greater than 30.
C) The data are clearly ratio.
D) The data are clearly nominal or ordinal.

Question 41

If the assumptions of parametric testing are not met, researchers must:

A) disregard this information and proceed with interpreting results.
B) make a decision to continue with parametric or nonparametric tests.
C) continue with nonparametric tests.
D) get a larger sample size.

Question 42

If one rejects the null hypothesis, the result is said to be:

A) acceptable.
B) important.
C) statistically significant.
D) valid.

Question 43

The typical probability adopted by researchers to determine whether a result is extreme is:

A) 0.01.
B) 0.05.
C) 0.25.
D) 0.50.

Question 44

The statistical concept of p levels is often referred to as:

A) betas.
B) alphas.
C) central tendency.
D) variability.

Question 45

Use the following to answer questions
Study Description: Tail Wagging
A New York Times article published on April 24, 2007, reported the research of Dr.Giorgio Vallortigara, a neuroscientist at the University of Trieste, Italy, and his two colleagues.The researchers asked whether a dog wags its tail in a preferred direction in response to positive stimuli and in another direction in response to negative stimuli.To answer their question, they recruited 30 dogs that were family pets.Filming each dog from above, they allowed it to view (through a slat in its cage) three positive stimuli separately, in order of descending positivity: its owner, an unfamiliar human, and a cat.All the dogs responded by wagging their tails to the right.But when the dogs were presented with an unfamiliar, aggressive dog, a negative stimulus, all dogs wagged their tails to the left.
(Study Description: Tail Wagging) Which statement is the research hypothesis for this study?

A) A dog's tail will wag more to the left in response to positive stimuli and more to the right in response to negative stimuli.
B) There will be no difference in a dog's tail wagging while viewing positive and negative stimuli.
C) A dog's tail will wag differently in response to positive stimuli than to negative stimuli.
D) A dog's tail will wag more to the right in response to positive stimuli and more to the left in response to negative stimuli.

Question 46

When calculating a z test, one compares data from the sample to a:

A) sample distribution.
B) population distribution.
C) distribution determined by the null hypothesis.
D) distribution determined by the research hypothesis.

Question 47

The research hypothesis states that:

A) the sample being studied is different from the population from which it was drawn.
B) nothing exists.
C) the null hypothesis is not correct.
D) there are no differences between the populations being studied.

Question 48

The area in the tails of the comparison distribution in which the null hypothesis can be rejected is called the _____.

A) critical value
B) cutoff
C) p level
D) critical region

Question 49

A hypothesis test is said to be _____ when it produces fairly accurate results, even when some of the assumptions underlying the hypothesis test are violated.

A) robust
B) invincible
C) reliable
D) fair

Question 50

Use the following to answer questions
Study Description: Dance Dance Revolution
Unnithan, Houser, and Fernhall (2006) were interested in whether playing the game Dance Dance Revolution (DDR) affected the heart rate of overweight adolescents differently than it affected non-overweight adolescents.Twenty-two adolescents, 10 classified as overweight and 12 as not overweight, played DDR for 12 minutes, while the researchers measured each participant's heart rate.On average, the researchers found no difference between the heart rate of the two groups.
(Study Description: Dance Dance Revolution) Which statement is the null hypothesis for this study?

A) There will be no difference in the heart rate of the two groups after playing Dance Dance Revolution.
B) The heart rate of the overweight group will be faster than that of the non-overweight group after both groups play Dance Dance Revolution.
C) The heart rate of the non-overweight group will be faster than that of the overweight group after both groups play Dance Dance Revolution.
D) The heart rates of the overweight group and the non-overweight group will differ after both groups play Dance Dance Revolution.

Question 51

If one fails to reject the null hypothesis, the result is said to be:

A) unacceptable.
B) unimportant.
C) not statistically significant.
D) valid.

Question 52

Use the following to answer questions
Study Description: Tail Wagging
A New York Times article published on April 24, 2007, reported the research of Dr.Giorgio Vallortigara, a neuroscientist at the University of Trieste, Italy, and his two colleagues.The researchers asked whether a dog wags its tail in a preferred direction in response to positive stimuli and in another direction in response to negative stimuli.To answer their question, they recruited 30 dogs that were family pets.Filming each dog from above, they allowed it to view (through a slat in its cage) three positive stimuli separately, in order of descending positivity: its owner, an unfamiliar human, and a cat.All the dogs responded by wagging their tails to the right.But when the dogs were presented with an unfamiliar, aggressive dog, a negative stimulus, all dogs wagged their tails to the left.
(Study Description: Tail Wagging) Which statement is the null hypothesis for this study?

A) A dog will wag its tail more to the left in response to positive stimuli and more to the right in response to negative stimuli.
B) A dog's tail wagging will be the same in response to positive stimuli as to negative stimuli.
C) A dog will wag its tail differently in response to positive stimuli than to negative stimuli.
D) A dog's tail will wag more to the right in response to positive stimuli and more to the left in response to negative stimuli.

Question 53

One rejects the null hypothesis only when:

A) the sample mean is larger than the population mean.
B) the p value associated with the test statistic is smaller than the p level chosen.
C) the sample mean is smaller than the population mean.
D) the p value associated with the test statistic is greater than the p level chosen.

Question 54

The phrase statistically significant means that the:

A) research finding is not important.
B) research finding is of practical importance.
C) research result was unlikely to have occurred by chance.
D) research finding is of theoretical importance.

Question 55

The _____ level is the probability used to determine the critical values, or cutoffs, in hypothesis testing.

A) z
B) M
C) p
D) s

Question 56

The _____ hypothesis is usually the "boring" one.

A) null
B) research
C) normalized
D) standard

Question 57

One rejects the null hypothesis when the test statistic falls in which area of the distribution?

A) critical value
B) critical region
C) region of determination
D) probability region

Question 58

Inferential statistical analyses that are based on a set of assumptions about the underlying population are:

A) inaccurate.
B) permissible only when certain assumptions about the sample are met.
C) nonparametric tests.
D) parametric tests.

Question 59

The null hypothesis states that:

A) the sample being studied is different from the population from which it was drawn.
B) nothing exists.
C) a difference exists between the populations being studied.
D) there are no differences between the populations being studied.

Question 60

The _____ hypothesis is usually the "exciting" one.

A) null
B) research
C) normalized
D) standard

Question 61

Claire knows the z score for her research hypothesis is -2.05, and her critical values are -1.96 and 1.96 for a p value of 0.05.What should she conclude about her hypothesis given these statistics?

A) She should reject the null hypothesis and report the direction of the effect because the score is in a critical region (below -1.96).
B) She should reject the null hypothesis but not report the direction of the effect because she doesn't have enough information.
C) She should fail to reject the null hypothesis because the score is not in a critical region (above 1.96 or below -1.96).
D) She should fail to reject the null hypothesis because she doesn't have enough information.

Question 62

Mehl (2007) published a study in the journal Science reporting the results of an extensive study of 396 men and women comparing the number of words uttered per day by each sex.If Mehl was testing the idea that women talk more than men, what type of hypothesis test would he conduct?

A) one-tailed test
B) two-tailed test
C) nonparametric test
D) z test

Question 63

If we conduct the same study with different samples and get the same results each time, it is:

A) more likely we have an error in our results.
B) more likely the results are accurate.
C) less likely the results are accurate.
D) less likely we can reject the null hypothesis.

Question 64

The statement "It is hypothesized that men and women will differ on reaction time measures" best illustrates a:

A) one-tailed test.
B) two-tailed test.
C) null hypothesis.
D) z test.

Question 65

When hypothesis testing, a more common approach is to use a _____ rather than a _____.

A) two-tailed test; one-tailed test
B) one-tailed test; two-tailed test
C) null hypothesis; research hypothesis
D) research hypothesis; null hypothesis

Question 66

The symbol for the null hypothesis is _____ and the symbol for the research hypothesis is _____.

A) H₁; H₀
B) H₀; H₁
C) $\mu$ ; M
D) $\mu$ ₀; $\mu$ ₁

Question 67

A major reason replication of scientific findings has rarely been attempted is because:

A) there is pressure to not question other researchers' findings.
B) journals tend to publish only new research.
C) of lack of interest in other researchers' work.
D) the media uses these results to criticize previous research.

Question 68

The z table only allows for the calculation of percentiles for positive z values.

Question 69

When multiple researchers recruit participants from various locations to replicate findings it is called:

A) crowd-sourcing science.
B) stealing other researchers' work.
C) independent science.
D) new research.

Question 70

The z table only allows for the calculation of percentiles for negative z values.

Question 71

Rose believes there is a positive correlation between watching violence on television and aggressive behavior.What would be her null hypothesis?

A) Watching violent TV shows increases aggressive behavior.
B) Watching violent TV shows is not related to level of aggressive behavior.
C) Watching violent TV shows causes aggressive behavior.
D) Only aggressive people watch violent TV shows.

Question 72

The statement, "It is hypothesized that participants in a stress condition will perform in a significantly different manner than participants in a control group on a series of memory tasks" best illustrates a:

A) one-tailed test.
B) two-tailed test.
C) null hypothesis.
D) z test.

Question 73

Use the following to answer questions
Study Description: Dance Dance Revolution
Unnithan, Houser, and Fernhall (2006) were interested in whether playing the game Dance Dance Revolution (DDR) affected the heart rate of overweight adolescents differently than it affected non-overweight adolescents.Twenty-two adolescents, 10 classified as overweight and 12 as not overweight, played DDR for 12 minutes, while the researchers measured each participant's heart rate.On average, the researchers found no difference between the heart rate of the two groups.
(Study Description: Dance Dance Revolution) Which statement is the research hypothesis for this study?

A) There will be no difference in the heart rates of the two groups after both groups play Dance Dance Revolution.
B) The heart rate of the overweight group will be faster than that of the non-overweight group after both groups play Dance Dance Revolution.
C) The heart rate of the non-overweight group will be faster that of the overweight group after both groups play Dance Dance Revolution.
D) The heart rates of the overweight group and the non-overweight group will differ after both groups play Dance Dance Revolution.

Question 74

If studies fail to replicate:

A) it is unlikely the original study is accurate.
B) science is a failure itself.
C) it can help us better understand the context under which findings might exist.
D) it confuses our understanding of the original study.

Question 75

The critical value(s) associated with a p level of 0.05 for a two-tailed hypothesis test using the z statistic is (are):

A) 1.96.
B) 1.65.
C) -1.65 and 1.65.
D) -1.96 and 1.96.

Question 76

The behavioral sciences typically use alpha of 0.05.How do they represent this value and what does it mean?

A) A p value, which means scores in the most extreme 2.5 percent on either end of the distribution, will be evidence to reject the null hypothesis.
B) A p value, which means scores 5 percent on either side of the mean, will be evidence to reject the null hypothesis.
C) A z statistic, which means scores in the most extreme 2.5 percent on either end of the distribution, will be evidence to reject the null hypothesis.
D) A z statistic, which means scores 5 percent on either side of the mean, will be evidence to reject the null hypothesis.

Question 77

The crowd-sourcing movement in research is:

A) closed science.
B) new science.
C) open science.
D) dirty science.

Question 78

Replication involves conducting:

A) the same study with similar samples and getting the same results each time.
B) the same study with different samples and getting the same results each time.
C) the same study with the same sample and getting the same results each time.
D) two different studies with the same sample and getting the same results each time.

Question 79

The critical value(s) associated with a p level of 0.05 for a one-tailed hypothesis test using the z statistic is (are):

A) 1.96.
B) 1.65.
C) -1.65 or 1.65.
D) -1.96 and 1.96.

Question 80

The statement "It is hypothesized that children who participate in a mentoring program will score lower on depression tests compared to children who do not participate in a mentoring program" best illustrates a:

A) one-tailed test.
B) two-tailed test.
C) null hypothesis.
D) z test.