Question 1

Our assumption that population variances are equal is called the assumption of

Accepted Answer

A)  equal dispersion. 
B)  heterogeneity of variance. 
C)  homogeneity of variance. 
D)  pooled variances. 
A)  equal dispersion. 
B)  heterogeneity of variance. 
C)  homogeneity of variance. 
D)  pooled variances.

Question 2

When variables A and B are independent, the variance of A - B is equal to

Accepted Answer

A)  the variance of A plus the variance of B. 
B)  the variance of A. 
C)  variance of A minus the variance of B. 
D)  it cannot be determined from the information given here. 
A)  the variance of A plus the variance of B. 
B)  the variance of A. 
C)  variance of A minus the variance of B. 
D)  it cannot be determined from the information given here.

Question 3

A chess team advisor wanted to examine how long it took his top two players, Fishy Bobber and Chet Mate, to complete their moves. Over the course of 50 matches each, Fishy averaged 330 seconds to move while Chet averaged 420 seconds to move. If the overall standard deviation for Fishy and Chet was 45 seconds, what was the effect size of their difference?

Accepted Answer

A)  1.0 
B)  90 
C)  2.0 
D)  Not enough information is given. 
A)  1.0 
B)  90 
C)  2.0 
D)  Not enough information is given.

Question 4

For a very conservative test when we don't pool the variances we should

Accepted Answer

A)  work at a = .01 instead of a = .05. 
B)  insist that the critical value of t be twice the tabled value. 
C)  use a much reduced number of degrees of freedom. 
D)  throw up our hands and call the problem too difficult. 
A)  work at a = .01 instead of a = .05. 
B)  insist that the critical value of t be twice the tabled value. 
C)  use a much reduced number of degrees of freedom. 
D)  throw up our hands and call the problem too difficult.

Question 5

The reason that we pool variances is to

Accepted Answer

A)  inflate our error term. 
B)  get a better estimate of error variance. 
C)  reduce the sample variance. 
D)  increase the size of t . 
A)  inflate our error term. 
B)  get a better estimate of error variance. 
C)  reduce the sample variance. 
D)  increase the size of t .

Question 6

When we have an independent sample t test, the degrees of freedom are equal to

Accepted Answer

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

Question 7

A weighted average is

Accepted Answer

A)  the average of two weights. 
B)  an average that gives greater influence to the larger sample. 
C)  an average that reduces the influence of the larger sample. 
D)  the balance between the sample size and the mean. 
A)  the average of two weights. 
B)  an average that gives greater influence to the larger sample. 
C)  an average that reduces the influence of the larger sample. 
D)  the balance between the sample size and the mean.

Question 8

One of our best aids in handling problems of non-normality is

Accepted Answer

A)  the variance sum law. 
B)  the central limit theorem. 
C)  the non-normality correction. 
D)  the Stroop test. 
A)  the variance sum law. 
B)  the central limit theorem. 
C)  the non-normality correction. 
D)  the Stroop test.

Question 9

If we reject the null hypothesis with a two-tailed test in the previous anorexia condition, we would side with which of the following alternatives?

Accepted Answer

A)  m FT = m C 
B)  m FT ≠ m C 
C)  m FT m C 
D)  m FT > m C 
A)  m FT = m C 
B)  m FT ≠ m C 
C)  m FT m C 
D)  m FT > m C

Question 10

Which of the following formulae for t is correct?

Accepted Answer

A)    
B)    
C)    
D)  all of the above 
A)    
B)    
C)    
D)  all of the above

Question 11

When we speak about pooling variances we are referring to

Accepted Answer

A)  averaging the two groups' variances. 
B)  using the variance of the larger group. 
C)  adding up the variances in each of two groups and dividing by 2. 
D)  taking the variance of both sets of data combined. 
A)  averaging the two groups' variances. 
B)  using the variance of the larger group. 
C)  adding up the variances in each of two groups and dividing by 2. 
D)  taking the variance of both sets of data combined.

Question 12

In deciding whether or not to pool the variances in calculating a t score, one should consider

Accepted Answer

A)  the differences in the sample variances. 
B)  the differences in the sample sizes. 
C)  both a and b 
D)  neither a nor b 
A)  the differences in the sample variances. 
B)  the differences in the sample sizes. 
C)  both a and b 
D)  neither a nor b

Question 13

To go from the equation in the previous problem to the equation for t we must

Accepted Answer

A)  substitute sample means for population means. 
B)  substitute sample variances for population variances. 
C)  substitute sample standard deviations for population variances. 
D)  draw very large samples. 
A)  substitute sample means for population means. 
B)  substitute sample variances for population variances. 
C)  substitute sample standard deviations for population variances. 
D)  draw very large samples.

Question 14

The most important characteristic of two independent samples is

Accepted Answer

A)  we measure the same subjects on two separate times. 
B)  the subjects in one sample are part of the same family as subjects in the other sample. 
C)  the set of scores for one sample is uncorrelated with the scores in the other sample. 
D)  the subjects in a group are people who know each other. 
A)  we measure the same subjects on two separate times. 
B)  the subjects in one sample are part of the same family as subjects in the other sample. 
C)  the set of scores for one sample is uncorrelated with the scores in the other sample. 
D)  the subjects in a group are people who know each other.

Question 15

What is the two-tail critical value for an independent samples t-test (assuming heterogeneity of variance) given the following samples sizes and p = .05? 
a. N1 = 10; N2 = 10 
b. N1 = 15; N2 = 10 
c. N1 = 27; N2 = 25

Accepted Answer

a. 2.101

Question 16

Calculate the pooled variance given the following information. 
a. s12 = 26, N1 = 30 and s22 = 32, N2 = 40 
b. s12 = 3.5, N1 = 12 and s22 = 4.6, N2 = 18

Accepted Answer

Question 17

Using the data from the previous example, what is the 95% confidence interval for the true difference in speed?

Accepted Answer

p (1.634 ≤

Question 18

When testing the means of independent samples, the null hypothesis is best thought of as

Accepted Answer

A)  the mean of population 1 is equal to the mean of population 2. 
B)  the mean of population 1 is unequal to the mean of population 2. 
C)  the mean of a set of difference scores is equal to 0. 
D)  the two population means don't differ by more than 10 points. 
A)  the mean of population 1 is equal to the mean of population 2. 
B)  the mean of population 1 is unequal to the mean of population 2. 
C)  the mean of a set of difference scores is equal to 0. 
D)  the two population means don't differ by more than 10 points.

Question 19

When we say that two independent variables, such as gender and age, are confounded, we mean that

Accepted Answer

A)  one variable blocks the influence of the other. 
B)  we cannot completely tell the effect of gender apart from the effect of age. 
C)  we cannot do anything with the study. 
D)  the data were collected carelessly. 
A)  one variable blocks the influence of the other. 
B)  we cannot completely tell the effect of gender apart from the effect of age. 
C)  we cannot do anything with the study. 
D)  the data were collected carelessly.

Question 20

In the example in the text assessing the effect of family therapy on anorexic girls by the mean levels of weight gain, the difference between the independent samples design used there and the related means design used in Chapter 13 is that the independent samples design

Accepted Answer

A)  compared the mean weight gained by anorexic girls in family therapy to the mean weight gained by girls in a control group. 
B)  compared the means of pre-therapy weights to the means of post-therapy weights. 
C)  assumed the weight gains of the two groups would be related. 
D)  assessed family therapy as a predictor of weight gain. 
A)  compared the mean weight gained by anorexic girls in family therapy to the mean weight gained by girls in a control group. 
B)  compared the means of pre-therapy weights to the means of post-therapy weights. 
C)  assumed the weight gains of the two groups would be related. 
D)  assessed family therapy as a predictor of weight gain.

Our assumption that population variances are equal is called the assumption of

When variables A and B are independent, the variance of A - B is equal to

For a very conservative test when we don't pool the variances we should

The reason that we pool variances is to

When we have an independent sample t test, the degrees of freedom are equal to

A weighted average is

One of our best aids in handling problems of non-normality is

If we reject the null hypothesis with a two-tailed test in the previous anorexia condition, we would side with which of the following alternatives?

Which of the following formulae for t is correct?

When we speak about pooling variances we are referring to

In deciding whether or not to pool the variances in calculating a t score, one should consider

To go from the equation in the previous problem to the equation for t we must

The most important characteristic of two independent samples is

What is the two-tail critical value for an independent samples t-test (assuming heterogeneity of variance) given the following samples sizes and p = .05? a. N₁ = 10; N₂ = 10 b. N₁ = 15; N₂ = 10 c. N₁ = 27; N₂ = 25

Calculate the pooled variance given the following information. a. s₁² = 26, N₁ = 30 and s₂² = 32, N₂ = 40 b. s₁² = 3.5, N₁ = 12 and s₂² = 4.6, N₂ = 18

Using the data from the previous example, what is the 95% confidence interval for the true difference in speed?

When testing the means of independent samples, the null hypothesis is best thought of as

When we say that two independent variables, such as gender and age, are confounded, we mean that

In the example in the text assessing the effect of family therapy on anorexic girls by the mean levels of weight gain, the difference between the independent samples design used there and the related means design used in Chapter 13 is that the independent samples design

Introduction

Basic Concepts

Displaying Data

Measures of Central Tendency

Measures of Variability

The Normal Distribution

Basic Concepts of Probability

Sampling Distributions and Hypothesis Testing

Correlation

Regression

Multiple Regression

Hypothesis Tests Applied to Means: One Sample

Hypothesis Tests Applied to Means: Two Related Samples

Power

One-Way Analysis of Variance

Factorial Analysis of Variance

Repeated-Measures Analysis of Variance

Chi-Square

Nonparametric and Resampling Statistical Tests

Meta-Analysis

Filters

Exam 14: Hypothesis Tests Applied to Means: Two Independent Samples

Our assumption that population variances are equal is called the assumption of

When variables A and B are independent, the variance of A - B is equal to

For a very conservative test when we don't pool the variances we should

The reason that we pool variances is to

When we have an independent sample t test, the degrees of freedom are equal to

A weighted average is

One of our best aids in handling problems of non-normality is

If we reject the null hypothesis with a two-tailed test in the previous anorexia condition, we would side with which of the following alternatives?

Which of the following formulae for t is correct?

When we speak about pooling variances we are referring to

In deciding whether or not to pool the variances in calculating a t score, one should consider

To go from the equation in the previous problem to the equation for t we must

The most important characteristic of two independent samples is

What is the two-tail critical value for an independent samples t-test (assuming heterogeneity of variance) given the following samples sizes and p = .05? a. N1 = 10; N2 = 10 b. N1 = 15; N2 = 10 c. N1 = 27; N2 = 25

Calculate the pooled variance given the following information. a. s12 = 26, N1 = 30 and s22 = 32, N2 = 40 b. s12 = 3.5, N1 = 12 and s22 = 4.6, N2 = 18

Using the data from the previous example, what is the 95% confidence interval for the true difference in speed?

When testing the means of independent samples, the null hypothesis is best thought of as

When we say that two independent variables, such as gender and age, are confounded, we mean that

In the example in the text assessing the effect of family therapy on anorexic girls by the mean levels of weight gain, the difference between the independent samples design used there and the related means design used in Chapter 13 is that the independent samples design

Introduction

Basic Concepts

Displaying Data

Measures of Central Tendency

Measures of Variability

The Normal Distribution

Basic Concepts of Probability

Sampling Distributions and Hypothesis Testing

Correlation

Regression

Multiple Regression

Hypothesis Tests Applied to Means: One Sample

Hypothesis Tests Applied to Means: Two Related Samples

Power

One-Way Analysis of Variance

Factorial Analysis of Variance

Repeated-Measures Analysis of Variance

Chi-Square

Nonparametric and Resampling Statistical Tests

Meta-Analysis

Filters

What is the two-tail critical value for an independent samples t-test (assuming heterogeneity of variance) given the following samples sizes and p = .05? a. N₁ = 10; N₂ = 10 b. N₁ = 15; N₂ = 10 c. N₁ = 27; N₂ = 25

Calculate the pooled variance given the following information. a. s₁² = 26, N₁ = 30 and s₂² = 32, N₂ = 40 b. s₁² = 3.5, N₁ = 12 and s₂² = 4.6, N₂ = 18