Deck 10: Hypothesis Testing III: the Analysis of Variance

Question 1

In a test using ANOVA,the average ages of three different samples are 37.56,37.57,37.58.This pattern would be consistent with the assumption that the

A)null hypothesis is false.
B)null hypothesis is true.
C)research hypothesis is false.
D)sample standard deviations approach zero.

Answer 1

null hypothesis is true.

Question 2

When we have an interval-ratio dependent variable and are comparing two groups,the appropriate test of significance is the ____.When we have an interval-ratio dependent variable and are comparing three or more groups,the appropriate test of significance is the ____.

A)t test,ANOVA
B)ANOVA,t test
C)chi square,ANOVA
D)t test,chi square

Answer 2

t test,ANOVA

Question 3

In the ANOVA test,if the null hypothesis is true

A)the sample standard deviations should be zero.
B)the sample means should be roughly equal in value.
C)the population means should be very different from each other .
D)alpha should be less than zero.

Answer 3

the sample means should be roughly equal in value.

Question 4

The population variance is a measure of

A)central tendency.
B)dispersion.
C)location.
D)degrees of freedom.

Question 5

The ANOVA test uses means and standard deviations to compare the amount of variation ____ with the amount of variation ____.

A)within categories,between categories
B)above categories,below categories
C)within sample means,between sample means
D)within sample standard deviations,between sample standard deviations

Question 6

What would be the most appropriate test of significance for research situations in which we have an interval-ratio dependent variable and an independent variable with three or more categories?

A)the t test
B)Chi square
C)ANOVA
D)the IQV

Question 7

With the ANOVA test,the ____ the difference between categories,relative to the differences within,the ____ likely that the null hypothesis will be rejected

A)smaller,more
B)greater,more
C)smaller,more.
D)b & c are both correct

Question 8

ANOVA proceeds by developing two separate estimates of the

A)population mean.
B)population standard deviation.
C)population variance.
D)sample variance.

Question 9

Stated generally,the null hypothesis for the ANOVA test is

A)m₁ = m₂ = m₃ = ...= m_k.
B)s₁ = s₂ = s₃ = ...= s_k.
C)SST = SSB = SSW.
D)dfb = dfw.

Question 10

If we reject the null hypothesis in a test using analysis of variance,we are concluding that

A)the populations from which our samples come are different.
B)the variables are independent.
C)the population variances are the same.
D)the sample means are significantly different.

Question 11

The null hypothesis for ANOVA states that

A)the variables are independent.
B)the variables are related.
C)the population means are equal.
D)the population means are different.

Question 12

A researcher is analyzing regional differences in family size.She has information on number of children for samples of families from four regions.Which of the following would be an appropriate statistical test?

A)t test for matched samples
B)t test for difference in means
C)ANOVA
D)Actually,none of the above would work in this situation

Question 13

ANOVA is appropriate for situations in which

A)only nominal level variables are involved.
B)we are comparing more than two samples.
C)bivariate tables are used to organize the data.
D)there are fewer than two samples.

Question 14

A researcher is comparing random samples of white,black,and Hispanic Americans for differences in income,family size,and years of education.Which of the following tests of significance would be useful for all three dependent variables?

A)t test for small samples
B)t test for difference in means
C)ANOVA
D)the test for the significance of the difference between sample proportions

Question 15

We have rejected the null hypothesis in an ANOVA test.This means that the variation ____ the samples is significantly greater than the variation ____ the samples.

A)within,between
B)above,below
C)outside,inside
D)between,within

Question 16

The ANOVA test is designed for dependent variables that have been measured at

A)the interval-ratio level.
B)the nominal level.
C)the ordinal level.
D)any level of measurement.

Question 17

ANOVA may be thought of as an extension of the ____.

A)confidence interval estimation procedure
B)t test for the significance of the difference between two sample proportions
C)t test for the significance of the difference between two sample means
D)t test for the significance of the difference between two matched samples

Question 18

In the ANOVA test,if the null hypothesis is false,the means of the different sample should be ____ and the standard deviation of the different samples should be ____.

A)similar in value,large in value
B)close to zero,equal to their respective variances
C)very different,lower in value then the means
D)very different in value,relatively low in value

Question 19

If we fail to reject the null hypothesis in a test using analysis of variance,we are concluding that

A)the populations from which our samples come are the same.
B)the samples are dependent.
C)the population variances are the different.
D)the sample means are different.

Question 20

A null hypothesis that states "the population means are equal" would be appropriate for which of the following tests of significance?

A)chi square
B)tests of proportions
C)ANOVA
D)Fisher's Exact test

Question 21

The F ratio is a ratio of ____ to ____.

A)amount of variation between categories to the amount of variation within
B)amount of variation within categories to the amount of variation between
C)total variation to amount of variation between
D)total variation to amount of variation within

Question 22

The sampling distribution for the ANOVA test is

A)the Z distribution.
B)the t distribution.
C)the F distribution.
D)none of the above

Question 23

The F ratio is equal to

A)SST - SSB.
B)the "mean square between" divided by the "mean square within."
C)the "mean square within" minus the "mean square between."
D)the total variance divided by the mean square between.

Question 24

The ANOVA test will tolerate some violation of the model assumptions as long as

A)sample size is quite small.
B)sample sizes are roughly equal.
C)at least one sample is greater than 50.
D)there are more than 4 separate samples.

Question 25

In the ANOVA test,if the null hypothesis is true,then

A)SSB should be at least twice as much as dfb.
B)SSW should be much greater than SSB.
C)the combined dfb and dfw should be much greater than the SST.
D)the mean square between and the mean square within should be roughly equal in value.

Question 26

Which of the following correctly states the relationship between SST (the total sum of squares),SSB (the sum of squares between),and SSW (the sum of squares within)?

A)SST = SSB + SSW
B)SST = SSB - SSW
C)SSW = SSB + SST
D)SSB = SST - SSW

Question 27

For ANOVA,we construct two estimates of the population variance.These are called

A)the average estimates.
B)the standard estimates.
C)the within and total estimates.
D)the mean square estimates.

Question 28

Which of the following is an assumption that must be made in Step 1 of the ANOVA test?

A)independent random samples
B)dependent random samples
C)level of measurement is nominal
D)stratified random samples

Question 29

To construct estimates of the population variance,we divide each sum of squares by its respective

A)degrees of freedom.
B)N.
C)category mean.
D)standard deviation.

Question 30

ANOVA is a one-tailed test and we are concerned only with those outcomes in which there is more variance

A)within categories than between categories.
B)between categories than within categories.
C)within populations than samples.
D)within samples than populations.

Question 31

The total sum of squares (SST)is found by subtracting the overall mean from ____ and squaring and summing the differences.

A)the category means
B)the category totals
C)each of the scores
D)the sum of squares between

Question 32

The quantity SSW measures the amount of variation

A)after subtracting the total variation (SST).
B)within the categories.
C)in the population.
D)assuming the null hypothesis is true.

Question 33

In the ANOVA test,what assumption must be made with regard to the population variances?

A)they are equal
B)they are unequal
C)they are both less than zero
D)they are equal to each other and to zero

Question 34

In the ANOVA test,the symbol 'dfw' refers to

A)the mean square estimate within.
B)degrees of freedom associated with SSW.
C)degrees forward without.
D)degrees of fullness,within estimate.

Question 35

In the ANOVA test,what assumption must be made about the shape of the population distribution?

A)the population distribution is normal in shape
B)the test is non-parametric,no assumption need be made about the population
C)population distribution is a bivariate table
D)the test is parametric,population distribution is assumed to not be normal

Question 36

In the ANOVA test,degrees of freedom within (dfw)are equal to ____ and degrees of freedom between (dfb)are equal to (k - 1).

A)(N - k)
B)(k + 1)
C)(N + k)
D)(k - N)

Question 37

In the ANOVA test,the symbol 'dfb' refers to

A)the mean square estimate between.
B)degrees of freedom associated with SSB.
C)degrees forward beneath.
D)degrees of fullness,behind estimate.

Question 38

The research hypothesis for the ANOVA test is

A)m₁ < m₂ < m₃ < ...< m_N.
B)at least one population mean is different.
C)SST = SSB = SSW.
D)at least one of the sums of squares is different.

Question 39

A useful computational shortcut for the ANOVA test is expressed as

A)SST = SSB/SSW.
B)dfw = dfb + SST.
C)SSW = SST - SSB.
D)SSB = SSW - SST.

Question 40

The ANOVA test is most appropriate for dependent variables that are

A)discrete and ordinal.
B)discrete and continuous.
C)continuous and nominal.
D)continuous and interval-ratio.

Question 41

One limitation of the ANOVA test is that it requires

A)nominal level dependent variables.
B)ordinal level independent variables.
C)very small samples.
D)an interval-ratio dependent variable.

Question 42

A researcher has analyzed differences in average College Board scores for random samples of students from four different colleges.The obtained F score is 0.45.What can be concluded about the null hypothesis?

A)Nothing,more information is needed.
B)Reject,the differences did not occur by random chance.
C)Fail to reject,differences are not statistically significant.
D)Fail to reject,differences are statistically significant.

Question 43

One limitation of ANOVA is that,when the null hypothesis is rejected,the test

A)does not tell us which sample mean(s)is/are different.
B)tells us nothing about the standard deviations.
C)does not tell us which population variances are zero.
D)does not tell us which population variances are greater than zero.

Question 44

A random sample of 15 families representing three social classes has been observed for the frequency with which the parents administer physical punishment to the children over a period of a week.Are the differences significant? Use the five step model as a guide and write a sentence or two of interpretation for your results.

Question 45

According to the tests reported in the text,which group had the most sex partners over the past five years?

A)never married
B)widowed
C)divorced
D)married

Question 46

In the ANOVA test,degrees of freedom within (dfw)are equal to (N - k)and degrees of freedom between (dfb)are equal to ____.

A)(N - k)
B)(k - 1)
C)(N + k)
D)(k - N)

Question 47

Very large random samples of Catholics,Protestants,and people with no religious affiliation have been questioned about their opinions on capital punishment.On a ten point scale,the Protestants average 6.8,the Catholics averaged 7.0,and the "Nones" averaged 7.1.These differences were tested by ANOVA and found to be statistically significant.What is the most reasonable conclusion?

A)This is a statistically significant and important difference.
B)This difference may be statistically significant but it seems unimportant.
C)This difference is due to random chance.
D)The researcher should have used sample means rather than proportions in this situation.

Question 48

If our F (obtained)exceeds the F (critical),we

A)reject the null.
B)accept the null.
C)must recompute since this is mathematically impossible.
D)reject the research hypothesis.

Question 49

The text reported the results of a test of frequency of sexual activity by marital status.The null hypothesis was rejected which means that

A)sexual activity is significantly related to marital status.
B)there is no important relationship between these variables.
C)American society is becoming increasingly promiscuous.
D)there is a 50% chance that these variables are related in the population.

Question 50

In an ANOVA test,when the null hypothesis is rejected,we know that at least one of the means is significantly different from the others.In order to find out which mean(s)are significantly different,we must conduct a

A)t test.
B)post hoc test.
C)post mortem test.
D)chi square test.

Question 51

According to the tests reported in the text,which of the following is true?

A)divorced individuals had significantly higher rates of sexual activity than any other group
B)widowed individuals were not significantly different from the other groups in their rate of sexual activity
C)married individuals had a significantly higher frequency of sex than any other group
D)single individuals reported significantly lower number of different sexual partners over the past five years

Question 52

In an ANOVA test,if MSB is significantly ____ than the MSW,we will ____.

A)less,reject the null hypothesis
B)greater,reject the null hypothesis
C)greater,fail to reject the null hypothesis
D)greater,recompute as this is mathematically impossible

Question 53

Three different sections of the same Interstate highway,with roughly equal traffic volumes,have been patrolled by the State Police at different levels of intensity for the past six months.The posted speed limit is 55 and the speeds of a random samples of motorists have been registered for each of the three sections.Is there any statistically significant difference in the speeds? Use the five step model as a guide and write a sentence or two of interpretation for your results.