Question 1

In testing for the significance of the difference between two sample means when the sample size is small,we may assume equal population variances if

Accepted Answer

A) sample sizes are exactly the same. 
B) sample sizes are varied. 
C) sample sizes are approximately equal. 
D) none of the above;we cannot assume equal population variance 
A) sample sizes are exactly the same. 
B) sample sizes are varied. 
C) sample sizes are approximately equal. 
D) none of the above;we cannot assume equal population variance C

Question 2

Samples of Republicans and Democrats have been tested for their level of support for welfare reform and the null hypothesis has been rejected.What may we conclude?

Accepted Answer

A) the difference is significant,there are differences between the parties on this issue 
B) the difference is significant,the parties are the same on this issue 
C) the difference is not significant 
D) a Type I error has occurred 
A) the difference is significant,there are differences between the parties on this issue 
B) the difference is significant,the parties are the same on this issue 
C) the difference is not significant 
D) a Type I error has occurred A

Question 3

When testing for the significance of the difference between two sample means,which parameters must be estimated with sample values?

Accepted Answer

A) the population standard deviations 
B) the population means 
C) the standard deviation of the sampling distribution 
D) the alpha value 
A) the population standard deviations 
B) the population means 
C) the standard deviation of the sampling distribution 
D) the alpha value A

Question 4

When testing for the significance of the difference between two samples,the null hypothesis states that the ____ are the same.

Accepted Answer

A) sample means 
B) population means 
C) sampling distributions 
D) population standard deviations 
A) sample means 
B) population means 
C) sampling distributions 
D) population standard deviations

Question 5

Four tests of significance were conducted on the same set of results:
For test 1: alpha = 0.05,two-tailed test.
For test 2: alpha = 0.10,one-tailed test.
For test 3: alpha = 0.01,two-tailed test.
For test 4: alpha = 0.01,one-tailed test.
Which test is most likely to result in a rejection of the null hypothesis?

Accepted Answer

A) Test 1 
B) Test 2 
C) Test 3 
D) Test 4 
A) Test 1 
B) Test 2 
C) Test 3 
D) Test 4

Question 6

Rejection of the null hypothesis in the two-sample case implies that the

Accepted Answer

A) samples are different on the trait of interest. 
B) populations from which the samples are drawn are different on the trait of interest. 
C) samples are not different on the trait of interest. 
D) populations from which the samples are drawn are not different on the trait of interest. 
A) samples are different on the trait of interest. 
B) populations from which the samples are drawn are different on the trait of interest. 
C) samples are not different on the trait of interest. 
D) populations from which the samples are drawn are not different on the trait of interest.

Question 7

For testing the difference between two sample means,the level of measurement is assumed to be

Accepted Answer

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

Question 8

The text reports the results of a test for the significance of the difference in average income for random samples of males and females.Males earned an average of about $17,000 more per year and the Z score computed in step 4 was 10.18.Given these results,which of the following is a reasonable conclusion?

Accepted Answer

A) The difference is statistically significant,large,and important. 
B) The difference is not statistically significant and was probably caused by random chance. 
C) There is no gender gap in income in the United States. 
D) This difference is statistically significant but quite small. 
A) The difference is statistically significant,large,and important. 
B) The difference is not statistically significant and was probably caused by random chance. 
C) There is no gender gap in income in the United States. 
D) This difference is statistically significant but quite small.

Question 9

Comparing gender differences in average education with differences in average income,we found

Accepted Answer

A) large and significant gender differences in education but no difference in income. 
B) no significant gender difference on either variable. 
C) large and significant gender differences in income but no difference in education. 
D) large and significant gender differences in both education and income. 
A) large and significant gender differences in education but no difference in income. 
B) no significant gender difference on either variable. 
C) large and significant gender differences in income but no difference in education. 
D) large and significant gender differences in both education and income.

Question 10

For tests of significance involving two sample proportions,the value of the population proportion is estimated from

Accepted Answer

A) the value of the sample means. 
B) the value of Z (obtained). 
C) the sample proportions. 
D) the sample standard deviations. 
A) the value of the sample means. 
B) the value of Z (obtained). 
C) the sample proportions. 
D) the sample standard deviations.

Question 11

A difference between samples that is shown to be statistically significant is always

Accepted Answer

A) theoretically important. 
B) practically important. 
C) sociologically important. 
D) none of the above 
A) theoretically important. 
B) practically important. 
C) sociologically important. 
D) none of the above

Question 12

When testing for the significance of the difference between two sample means,we must first estimate ____ before we can compute the test statistic.

Accepted Answer

A) the standard deviation of the sampling distribution 
B) the standard deviations of the samples 
C) the population means 
D) the critical region 
A) the standard deviation of the sampling distribution 
B) the standard deviations of the samples 
C) the population means 
D) the critical region

Question 13

Which of the following was true for the test for differences in average income by gender reported in the text?

Accepted Answer

A) the information on income came from the U.S.Bureau of the Census 
B) the income of males,on the average,was almost twice that of females 
C) the test compared only people who worked full time 
D) the test compared only people who had a least a high school education 
A) the information on income came from the U.S.Bureau of the Census 
B) the income of males,on the average,was almost twice that of females 
C) the test compared only people who worked full time 
D) the test compared only people who had a least a high school education

Question 14

When testing for the significance of the difference between two sample means,the null hypothesis can be stated as

Accepted Answer

A)  $\bar { X } _ { 1 } = \bar { X } _ { 2 }$ 
B) m > 0. 
C) m = m. 
D) s = s. 
A)  $\bar { X } _ { 1 } = \bar { X } _ { 2 }$ 
B) m > 0. 
C) m = m. 
D) s = s.

Question 15

The larger the sample size,the

Accepted Answer

A) more important the observed difference. 
B) more likely we are to reject the null hypothesis. 
C) less likely we are to reject the null hypothesis. 
D) lower the Z score. 
A) more important the observed difference. 
B) more likely we are to reject the null hypothesis. 
C) less likely we are to reject the null hypothesis. 
D) lower the Z score.

Question 16

When testing for the significance of the difference between two sample means,the standard deviation of the sampling distribution is estimated using

Accepted Answer

A) population standard deviations. 
B) the standard error of the means. 
C) degrees of freedom. 
D) sample standard deviations corrected for bias. 
A) population standard deviations. 
B) the standard error of the means. 
C) degrees of freedom. 
D) sample standard deviations corrected for bias.

Question 17

Very large random samples of Catholics and Protestants have been questioned about their opinions on cohabitation.Forty-six percent of the Protestant and 47% of the Catholics approve of males and females living together without being married.The difference has been tested and found to be statistically significant.What is the most reasonable conclusion?

Accepted Answer

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. 
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 18

To satisfy the requirement of independent random sampling,the researcher

Accepted Answer

A) must use only cluster sampling. 
B) may randomly select cases from one list of the population,then subdivide that sample according to the trait of interest. 
C) may randomly select an entire neighborhood,then select any member of each family in that neighborhood. 
D) must select only very small populations. 
A) must use only cluster sampling. 
B) may randomly select cases from one list of the population,then subdivide that sample according to the trait of interest. 
C) may randomly select an entire neighborhood,then select any member of each family in that neighborhood. 
D) must select only very small populations.

Question 19

If a difference between random samples is not statistically significant,it is probably ____.On the other hand,a statistically significant difference is not necessarily ____.

Accepted Answer

A) important,due to random chance 
B) unimportant,large 
C) important,unimportant 
D) unimportant,important 
A) important,due to random chance 
B) unimportant,large 
C) important,unimportant 
D) unimportant,important

Question 20

When is the t distribution used instead of the Z distribution to test the significance of the difference between two sample proportions?

Accepted Answer

A) never 
B) when sample size is very large 
C) when one sample is much larger than the other 
D) when N is small 
A) never 
B) when sample size is very large 
C) when one sample is much larger than the other 
D) when N is small

In testing for the significance of the difference between two sample means when the sample size is small,we may assume equal population variances if

Samples of Republicans and Democrats have been tested for their level of support for welfare reform and the null hypothesis has been rejected.What may we conclude?

When testing for the significance of the difference between two sample means,which parameters must be estimated with sample values?

When testing for the significance of the difference between two samples,the null hypothesis states that the ____ are the same.

Rejection of the null hypothesis in the two-sample case implies that the

For testing the difference between two sample means,the level of measurement is assumed to be

Comparing gender differences in average education with differences in average income,we found

For tests of significance involving two sample proportions,the value of the population proportion is estimated from

A difference between samples that is shown to be statistically significant is always

When testing for the significance of the difference between two sample means,we must first estimate ____ before we can compute the test statistic.

Which of the following was true for the test for differences in average income by gender reported in the text?

When testing for the significance of the difference between two sample means,the null hypothesis can be stated as

The larger the sample size,the

When testing for the significance of the difference between two sample means,the standard deviation of the sampling distribution is estimated using

To satisfy the requirement of independent random sampling,the researcher

If a difference between random samples is not statistically significant,it is probably .On the other hand,a statistically significant difference is not necessarily .

When is the t distribution used instead of the Z distribution to test the significance of the difference between two sample proportions?

Introduction

Basic Descriptive Statistics: Percentages, Ratios and Rates, Tables, Charts and Graphs

Measures of Central Tendency

Measures of Dispersion

The Normal Curve

Introduction to Inferential Statistics: Sampling and the Sampling Distribution

Estimation Procedures

Hypothesis Testing I: the One-Sample Case

Hypothesis Testing III: the Analysis of Variance

Hypothesis Testing Iv: Chi Square

Bivariate Association: Introduction and Basic Concepts

Association Between Variables Measured at the Nominal Level

Association Between Variables Measured at the Ordinal Level

Association Between Variables Measured at the Interval-Ratio Level

Elaborating Bivariate Tables

Partial Correlation and Multiple Regression and Correlation

Filters

Exam 9: Hypothesis Testing II: the Two-Sample Case

In testing for the significance of the difference between two sample means when the sample size is small,we may assume equal population variances if

Samples of Republicans and Democrats have been tested for their level of support for welfare reform and the null hypothesis has been rejected.What may we conclude?

When testing for the significance of the difference between two sample means,which parameters must be estimated with sample values?

When testing for the significance of the difference between two samples,the null hypothesis states that the ____ are the same.

Rejection of the null hypothesis in the two-sample case implies that the

For testing the difference between two sample means,the level of measurement is assumed to be

Comparing gender differences in average education with differences in average income,we found

For tests of significance involving two sample proportions,the value of the population proportion is estimated from

A difference between samples that is shown to be statistically significant is always

When testing for the significance of the difference between two sample means,we must first estimate ____ before we can compute the test statistic.

Which of the following was true for the test for differences in average income by gender reported in the text?

When testing for the significance of the difference between two sample means,the null hypothesis can be stated as

The larger the sample size,the

When testing for the significance of the difference between two sample means,the standard deviation of the sampling distribution is estimated using

To satisfy the requirement of independent random sampling,the researcher

If a difference between random samples is not statistically significant,it is probably ____.On the other hand,a statistically significant difference is not necessarily ____.

When is the t distribution used instead of the Z distribution to test the significance of the difference between two sample proportions?

Introduction

Basic Descriptive Statistics: Percentages, Ratios and Rates, Tables, Charts and Graphs

Measures of Central Tendency

Measures of Dispersion

The Normal Curve

Introduction to Inferential Statistics: Sampling and the Sampling Distribution

Estimation Procedures

Hypothesis Testing I: the One-Sample Case

Hypothesis Testing III: the Analysis of Variance

Hypothesis Testing Iv: Chi Square

Bivariate Association: Introduction and Basic Concepts

Association Between Variables Measured at the Nominal Level

Association Between Variables Measured at the Ordinal Level

Association Between Variables Measured at the Interval-Ratio Level

Elaborating Bivariate Tables

Partial Correlation and Multiple Regression and Correlation

Filters

If a difference between random samples is not statistically significant,it is probably .On the other hand,a statistically significant difference is not necessarily .