Deck 11: Correlated Groups T-Test

Question 1

Dr.Hinson wants to investigate if rats fed a diet enriched with omega will do better at a maze learning task then when these same rats are given a normal diet.He has a total of 30 rats for his experiment.If Dr.Hinson fails to implement the appropriate changes to his experiment a potential confound may be_____.

A)order effects
B)disturbance variance
C)ceiling effect
D)Both a & b

Answer 1

order effects

Question 2

Dr.August is investigating whether or not women have more job satisfaction after they are given praise or a gift card (different levels or rewards).She has recruited 10 women from Intel and for 6 months the women received praise then the next 6 months they received a gift card.The conditions were counterbalanced and a survey on job satisfaction was distributed following the treatment conditions or every 6 months until the research was completed.After finishing her study Dr.August was busy writing a grant,therefore she has asked you to analyze her data below.Please note the survey was based on 1-5 Likert scale with high scores indicating high job satisfaction and low score indicating dissatisfaction.
What is the nature of the relationship in Dr.Augusts' research?

A)when women received praise they had more job satisfaction
B)when women received a gift card they had more job satisfaction
C)she has a type II error so the results are not conclusive
D)the independent variable had no affect on job satisfaction
E)both c & d

Answer 2

when women received praise they had more job satisfaction

Question 3

Dr.August is investigating whether or not women have more job satisfaction after they are given praise or a gift card (different levels or rewards).She has recruited 10 women from Intel and for 6 months the women received praise then the next 6 months they received a gift card.The conditions were counterbalanced and a survey on job satisfaction was distributed following the treatment conditions or every 6 months until the research was completed.After finishing her study Dr.August was busy writing a grant,therefore she has asked you to analyze her data below.Please note the survey was based on 1-5 Likert scale with high scores indicating high job satisfaction and low score indicating dissatisfaction.
What is the strength of the relationship of the data above?

A).90
B).80
C).88
D).76

Answer 3

.90

Question 4

A correlated groups t-test is used when_____.

A)the independent variable is between subjects
B)the independent variable is within subjects
C)when subjects are matched on a particular variable
D)Both b & c
E)all of these

Question 5

Dr.Hinson wants to investigate if rats fed a diet enriched with omega will do better at a maze learning task then when these same rats are given a normal diet.He has a total of 30 rats for his experiment.In Dr.Hinson's study if he is using a total of 30 rats what is his degrees of freedom?

A)28
B)30
C)29
D)27

Question 6

Dr.August is investigating whether or not women have more job satisfaction after they are given praise or a gift card (different levels or rewards).She has recruited 10 women from Intel and for 6 months the women received praise then the next 6 months they received a gift card.The conditions were counterbalanced and a survey on job satisfaction was distributed following the treatment conditions or every 6 months until the research was completed.After finishing her study Dr.August was busy writing a grant,therefore she has asked you to analyze her data below.Please note the survey was based on 1-5 Likert scale with high scores indicating high job satisfaction and low score indicating dissatisfaction.
What statistical test should be used to analyze Dr.Augusts' data?

A)correlated-groups t test
B)independent-groups t test
C)two-sample independent z test
D)Pearson correlation

Question 7

Dr.Hinson wants to investigate if rats fed a diet enriched with omega will do better at a maze learning task then when these same rats are given a normal diet.He has a total of 30 rats for his experiment.What type of statistical test should Dr.Hinson use in analyze his data?

A)one-sample z test
B)independent-groups t test
C)correlated-groups t test
D)Pearson correlation

Question 8

Dr.August is investigating whether or not women have more job satisfaction after they are given praise or a gift card (different levels or rewards).She has recruited 10 women from Intel and for 6 months the women received praise then the next 6 months they received a gift card.The conditions were counterbalanced and a survey on job satisfaction was distributed following the treatment conditions or every 6 months until the research was completed.After finishing her study Dr.August was busy writing a grant,therefore she has asked you to analyze her data below.Please note the survey was based on 1-5 Likert scale with high scores indicating high job satisfaction and low score indicating dissatisfaction.
What should be done after the inference about the relationship has been determined?

A)eta-squared should be calculated
B)confidence intervals should be determined
C)a methods section should be written
D)None of these

Question 9

A correlated groups t-test is a parametric test and assumes_____.

A)the population is normally distributed
B)the population is normally skewed
C)the independent variable is measured on an ordinal scale
D)All of these
E)both a & c

Question 10

The 95% confidence interval for the mean differences is reported following _____.

A)one-sample z test
B)independent-groups t test
C)correlated-groups t test
D)Pearson correlation
E)both b & c

Question 11

Dr.Miguel is studying stages of verbal ability in kids.He test the kids on verbal ability at age 5 years then again at age of 7.What type of statistical test should he use to analyze his data?

A)one-sample z test
B)independent-groups t test
C)correlated-groups t test
D)Pearson correlation

Question 12

The main difference between a correlated groups t-test and Independent groups t-test include(s)_____.

A)an independent groups t-test assumes the distribution is normal
B)the correlated groups t-test assumes the independent variable is within subjects
C)the correlated groups t-test assumes the population mean is known
D)the independent groups t-test assumes the population means is known
E)none of these

Question 13

Dr.August is investigating whether or not women have more job satisfaction after they are given praise or a gift card (different levels or rewards).She has recruited 10 women from Intel and for 6 months the women received praise then the next 6 months they received a gift card.The conditions were counterbalanced and a survey on job satisfaction was distributed following the treatment conditions or every 6 months until the research was completed.After finishing her study Dr.August was busy writing a grant,therefore she has asked you to analyze her data below.Please note the survey was based on 1-5 Likert scale with high scores indicating high job satisfaction and low score indicating dissatisfaction.
Should the confidence intervals be included in the results section?

A)Yes,they should be included
B)no,this only pertains to independent groups t-test
C)Yes,but only if the results are not statistically significant
D)Both a & c

Question 14

Dr.August is investigating whether or not women have more job satisfaction after they are given praise or a gift card (different levels or rewards).She has recruited 10 women from Intel and for 6 months the women received praise then the next 6 months they received a gift card.The conditions were counterbalanced and a survey on job satisfaction was distributed following the treatment conditions or every 6 months until the research was completed.After finishing her study Dr.August was busy writing a grant,therefore she has asked you to analyze her data below.Please note the survey was based on 1-5 Likert scale with high scores indicating high job satisfaction and low score indicating dissatisfaction.
Which of the following statements best describes results of Dr.Augusts' alternative hypothesis?

A)µ₁=µ₂
B)µ₁?µ₂
C)µ=0
D)µ₁>0

Question 15

Dr.August is investigating whether or not women have more job satisfaction after they are given praise or a gift card (different levels or rewards).She has recruited 10 women from Intel and for 6 months the women received praise then the next 6 months they received a gift card.The conditions were counterbalanced and a survey on job satisfaction was distributed following the treatment conditions or every 6 months until the research was completed.After finishing her study Dr.August was busy writing a grant,therefore she has asked you to analyze her data below.Please note the survey was based on 1-5 Likert scale with high scores indicating high job satisfaction and low score indicating dissatisfaction.
What is the calculated t-value for Dr.Augusts' data above?

A)5.70
B)6.00
C)5.88
D)1.90

Question 16

Dr.August is investigating whether or not women have more job satisfaction after they are given praise or a gift card (different levels or rewards).She has recruited 10 women from Intel and for 6 months the women received praise then the next 6 months they received a gift card.The conditions were counterbalanced and a survey on job satisfaction was distributed following the treatment conditions or every 6 months until the research was completed.After finishing her study Dr.August was busy writing a grant,therefore she has asked you to analyze her data below.Please note the survey was based on 1-5 Likert scale with high scores indicating high job satisfaction and low score indicating dissatisfaction.
After calculating the t-value can you reject the null hypothesis? (Note she used a nondirectional test with the alpha level set at 0.05 so the table t was 2.776).

A)No,there was no affect of the independent variable
B)Yes,there was an affect of the independent variable
C)She needs to change her hypothesis
D)none of these

Question 17

Jake is working on his thesis and has two groups of subjects.A total of 10 subjects listened to music at 80 decibels which is considered loud.While the other 10 subjects listed to the same music at only 30 decibels which is soft.After 1 hour each groups was given a hearing test.However,he matched subjects before they were put into groups on hearing abilities.What statistical test should be used to analyze the data?

A)correlated-groups t test
B)independent-groups t test
C)two-sample independent z test
D)Pearson correlation

Question 18

Within subjects designs have several advantages which include_____.

A)a smaller sample size is needed
B)a larger sample size is needed
C)less disturbance variables
D)Both a & c
E)none of these

Question 19

Dr.August is investigating whether or not women have more job satisfaction after they are given praise or a gift card (different levels or rewards).She has recruited 10 women from Intel and for 6 months the women received praise then the next 6 months they received a gift card.The conditions were counterbalanced and a survey on job satisfaction was distributed following the treatment conditions or every 6 months until the research was completed.After finishing her study Dr.August was busy writing a grant,therefore she has asked you to analyze her data below.Please note the survey was based on 1-5 Likert scale with high scores indicating high job satisfaction and low score indicating dissatisfaction.
In Dr.Augusts' result section how should she report the results of the t-test you calculated for her?

A)t(9)= 1.90,p<0.05
B)t(4)= 6.00 p<0.05
C)t(5)= 5.88 p<0.05
D)None of these

Question 20

Dr.Hinson wants to investigate if rats fed a diet enriched with omega will do better at a maze learning task then when these same rats are given a normal diet.He has a total of 30 rats for his experiment.What should Dr.Hinson do before he starts his experiment?

A)counterbalance the diet so 15 rats receive omega then normal chow and 15 normal chow then omega diet
B)raise them on the appropriate omega diet before starting his experiment
C)measuring the speed of each rat can run before implementing the independent variable
D)All of these

Question 21

The major difference between the correlated groups t test and the independent groups t test is that the former is used when the independent variable is _____ in nature and the latter is used when the independent variable is _____ in nature.

A)between subjects;within subjects
B)within subjects;between subjects
C)quantitative;qualitative
D)qualitative;quantitative

Question 22

Which of the following conditions would make it inappropriate to use a correlated-groups t test?

A)The dependent variable has been measured on an interval level.
B)The dependent variable has been measured on a nominal level.
C)The independent variable has been classified as nominal.
D)The independent variable has only two levels.

Question 23

A reading readiness test is administered to 8 matched pairs of first graders.One child of each pair had 3 years of day care experience whereas the other child had none.The results of the test are shown in the following table.(Higher scores indicate greater readiness. )Assume á=.05,nondirectional test.
The df for this problem is _______.

A)14
B)6
C)7
D)12

Question 24

Which of the following statistical tests should be used to analyze the relationship between the independent and dependent variables when the independent variable is within-subjects?

A)one-sample z test
B)independent-groups t test
C)correlated-groups t test
D)Pearson correlation

Question 25

When the population means in the two conditions defining the difference scores are _____,the mean difference score across all individuals in the population will equal _____.

A)equivalent;0
B)nonequivalent;0
C)equivalent;1.0
D)none of these

Question 26

If your calculated t statistic was t(30)= 6.23,you would most likely decide to _____.

A)accept the null
B)reject the H₀
C)fail to reject the H₀
D)reject the H₁

Question 27

A reading readiness test is administered to 8 matched pairs of first graders.One child of each pair had 3 years of day care experience whereas the other child had none.The results of the test are shown in the following table.(Higher scores indicate greater readiness. )Assume á=.05,nondirectional test.
The critical t for this problem is ______.

A)2.447
B)3.707
C)1.943
D)2.179

Question 28

The mean of the sampling distribution of mean difference scores is equal to the _____ across individuals in the population.

A)difference scores
B)mean difference score
C)mean
D)standard error

Question 29

Which of the following conditions would preclude the use of a correlated-groups design?

A)small number of subjects
B)the experimental manipulation has known carry-over effects
C)the existence of individual differences
D)the presence of disturbance variables

Question 30

In the correlated groups t test,the relevant t distribution has _____ degrees of freedom associated with it.

A)N
B)N -1
C)N - 2
D)0

Question 31

If a researcher used a matched-subjects design,which of the following statistical tests should be used?

A)correlated-groups t test
B)independent-groups t test
C)two-sample independent z test
D)Pearson correlation

Question 32

A sampling distribution of the mean of difference scores can be defined as a _____ distribution consisting of mean difference scores across individuals for all possible random samples of a given size that could be selected from a population.

A)skewed
B)bimodal
C)normal
D)theoretical

Question 33

Which of the following statements describes a correlated-groups t test null hypothesis?

A)µ₁=µ₂
B)µ₁

µ₂
C)µ=0
D)µ₁>0

Question 34

The degrees of freedom associated with a correlated group t-test if the number of subjects is 10 is_____.

A)9
B)8
C)4
D)6

Question 35

When using a correlated-groups t test design,we calculate the degrees of freedom using ______,where N= number of difference scores.

A)N-1
B)N-2
C)n₁+n₂-2
D)n₁-2

Question 36

A correlated -groups t test can be used to analyze the relationship between two variables when _____.

A)the independent variable has only two levels
B)the independent variable is within-subjects
C)the dependent variable is measured on a ratio level
D)all of these

Question 37

The correlated groups t test is typically used to analyze the relationship between two variables when:

A)the independent variable is quantitative in nature and is measured on a level that at least approximates interval characteristics
B)the independent variable is within-subjects in nature
C)the independent variable has two and only two levels
D)all of these

Question 38

Usually,the correlated groups t test provides a _____ test of the relationship between the independent and dependent variables than does the independent groups t test.

A)more sensitive
B)less sensitive
C)statistically significant
D)nullified

Question 39

The standard deviation of the sampling distribution of mean difference scores is referred to as the _____ of difference scores.

A)mean difference
B)variance
C)standard error of the mean
D)sampling error

Question 40

An important advantage of the correlated groups t test over the independent groups t test relates to the control of:

A)random assignment
B)disturbance variables
C)confounding variables
D)all of these

Question 41

The variance extraction technique that creates nullified scores removes sources of variability that are due to _____.

A)individual differences
B)confounding variables
C)the dependent variable
D)all of these

Question 42

The procedure of _____ may be used in order to evenly distribute carry-over effects across conditions.

A)counterbalancing
B)countersampling
C)randomization
D)matching

Question 43

A correlated groups t test is analogous to an independent groups t test with the effects of individual differences _____ the _____.

A)added to;standard error
B)extracted from;independent variable
C)extracted from;dependent variable
D)extracted from;sample

Question 44

The correlated groups t test is _____ to violations of the normality assumption.

A)especially vulnerable
B)relatively robust
C)slightly robust
D)none of these

Question 45

If a correlated-groups t test found significant differences due to the independent variable,which of the following procedures would clarify the nature of the relationship?

A)removing the effects of individual differences
B)eta²
C)the p value
D)examination of the means of each condition

Question 46

In a correlated-groups t test,eta² represents the proportion of variability in the dependent variable that is associated with the independent variable ______.

A)before the variability due to individual differences has been removed
B)after the variability due to individual differences has been added
C)after the variance has been divided by df
D)after variability due to individual differences has been removed

Question 47

A reading readiness test is administered to 8 matched pairs of first graders.One child of each pair had 3 years of day care experience whereas the other child had none.The results of the test are shown in the following table.(Higher scores indicate greater readiness. )Assume á=.05,nondirectional test.
The calculated t for this problem is _____.

A).97
B)2.65
C).39
D)1.88

Question 48

If the effects of individual differences have not been removed from the raw scores,the eta² for the correlated-groups case would be _____ than if they have been removed,everything else being equal.

A)no different
B)smaller
C)larger
D)equal to or smaller

Question 49

Which of the following assumptions may be violated if a very large sample is used?

A)the independence assumption
B)the normality assumption
C)the assumption of random selection
D)none of the assumptions may be even slightly violated

Question 50

The correlated-groups t test is robust to violations of the normality assumption if _____.

A)the data is measured on a quantitative scale
B)there are homogeneous variances in the population
C)the population of difference scores is large
D)the sample size is relatively large

Question 51

When using the correlated groups t test,it is assumed that the _____ is normally distributed.

A)population of difference scores
B)sample of difference scores
C)sampling error
D)all of these

Question 52

The analysis of the nature of the relationship for the _____ involves examination of the mean scores for the two conditions.

A)correlated groups t test
B)independent groups t test
C)a and b
D)neither a nor b

Question 53

When we fail to reject the null hypothesis,the question of the nature of the relationship is:

A)meaningful
B)not meaningful
C)statistically significant
D)addressed by eta-squared

Question 54

If we were to compute the average nullified score across conditions for each individual in a correlated groups study,we would find that every individual would have _____ average score(s).

A)the same
B)different
C)higher
D)lower

Question 55

If the sample size of a study is small and a high value of eta squared is observed,but there is no statistically significant effect of the independent variable on the dependent variable,we may conclude that ______.

A)a mistake has been made since you can't get a strong relationship when the t is nonsignificant
B)unless a larger sample is used we can't be certain about the effects of the independent variable
C)although the sample is small,the strong relationship indicates there is an effect due to the independent variable
D)the nonsignificant finding should be taken as conclusive evidence of no effect of the independent variable

Question 56

In the correlated groups case,eta-squared represents the proportion of variability in the dependent variable that is associated with the independent variable after the variability due to _____ has been removed.

A)correlated errors
B)individual differences
C)all disturbance variables
D)nullified scores

Question 57

An important methodological problem to consider in a correlated-groups design is ______.

A)effects of individual differences
B)the need for a larger sample compared to an independent-groups design
C)the greater power of the test produces more Type I errors
D)carry-over effects of the independent variable

Question 58

A reading readiness test is administered to 8 matched pairs of first graders.One child of each pair had 3 years of day care experience whereas the other child had none.The results of the test are shown in the following table.(Higher scores indicate greater readiness. )Assume á=.05,nondirectional test.
The eta² for the "reading readiness" data is _____.

A).31
B).23
C).54
D).44

Question 59

The formula for computing eta-squared for the correlated groups t test is _____ that for the independent groups t test.

A)the same as
B)different than

Question 60

If the sample size is less than 15,the correlated groups t test may show inflated Type I errors for data that are:

A)normally distributed
B)cross-sectional
C)markedly skewed
D)markedly kurtotic

Question 61

Using Appendix

A)87
B)36
C)53
D)23
E)1,find the sample size that is need to detect a population eta² of .10,with a power of.80 and á=.05,nondirectional test.

Question 62

Based on the Method of Presentation section of Chapter 11,suppose a researcher is reporting the results of a correlated groups t test.If she obtained a t value of 2.17 with 10 subjects in each group using an alpha level of .05 and a nondirectional test,how would she report this in a psychological journal?

A)t (9)= 2.17,p < .05
B)t (9)= 2.17,p > .05
C)t (18)= 2.17,p < .05
D)t (18)= 2.17,p > .05

Question 63

The correlated groups t test is typically used to analyze the relationship between two variables when the independent variable is between-subjects in nature.

Question 64

Although the correlated t test is usually a more powerful statistical test than the independent groups t test,one exception to this is

A)when r is so close to 0 that the magnitude of estimated standard errors is comparable in the two tests.
B)when r is so close to 1 that the magnitude of estimated standard errors is comparable in the two tests.
C)when the n in both groups is unequal.
D)there are no exceptions to this statement.

Question 65

The mean of the sampling distribution of mean difference scores is equal to the mean difference score across individuals in the population.

Question 66

A correlated groups t test will usually (but not always)be _____ than a corresponding independent groups t test.

A)less powerful
B)less conservative
C)more powerful
D)more conservative

Question 67

A correlated groups t test is analogous to an independent groups t test with the effects of individual differences extracted from the dependent variable.

Question 68

The correlated groups t test provides a less sensitive test of the relationship between the independent and dependent variables than does the independent groups t test.

Question 69

One major source of "noise" in behavioral science data is the difference in backgrounds and abilities of the individuals participating in an investigation.

Question 70

Counterbalancing is a method to control for

A)small sample sizes.
B)disturbance variables.
C)confounding variables.
D)low statistical power.

Question 71

In most behavioral science research,the estimated standard error for the correlated groups t test is _____ than the estimated standard error for the independent groups t test applied to the same data.

A)more stable
B)less biased
C)larger
D)smaller

Question 72

If the researcher suspects that the strength of the relationship between two variables in the population is .25,what sample size should she use per group in a study involving two correlated groups and an alpha level of .05,directional test,in order to achieve a power of .90?

A)14
B)17
C)21
D)24

Question 73

The standard deviation of the sampling distribution of mean difference scores is referred to as the standard error of the difference.

Question 74

The major difference between the correlated groups t test and the independent groups t test is that the former is used when the independent variable is manipulated and the latter is used when the independent variable is observed.

Question 75

Between-subjects designs (but not within-subjects designs)allow us to estimate the source of variability due to the influence of individual differences,and extract it from the dependent variable.

Question 76

An important advantage of the correlated groups t test over the independent groups t test relates to the control of confounding variables.

Question 77

In most behavioral science research the estimated standard error for a correlated groups t test is _____than the estimated standard error for the independent groups t test.

A)the same
B)larger
C)smaller
D)sometimes larger,sometimes smaller,depending on the N

Question 78

If the researcher suspects that the strength of the relationship between two variables in the population is .07,what sample size should she use per group in a study involving two correlated groups and an alpha level of .05,nondirectional test,in order to achieve a power of .70?

A)32
B)42
C)56
D)65

Question 79

A sampling distribution of the mean of difference scores can be defined as a theoretical distribution consisting of mean difference scores across individuals for all possible random samples of a given size that could be selected from a population.

Question 80

A test's sensitivity can be defined as its ability to detect a relationship between variables when a relationship exists in the population.