Question 1

The assumption of homogeneity of variance means that

Accepted Answer

A)  the scores in the two populations are homogeneous in that they show little variability 
B)  the scores in the two populations are equally variable 
C)  the scores in the two samples are homogeneous in that they show little variability 
D)  the scores in the two samples are equally variable 
A)  the scores in the two populations are homogeneous in that they show little variability 
B)  the scores in the two populations are equally variable 
C)  the scores in the two samples are homogeneous in that they show little variability 
D)  the scores in the two samples are equally variable B

Question 2

Suppose that X and Y stand for scores on a test of learning under conditions of reward and punishment, respectively. If we are interested only in whether reward results in higher scores than punishment, and obtain the difference between the two conditions in terms of   
, we should place the region of rejection

Accepted Answer

A)  entirely in the right tail of the sampling distribution 
B)  entirely in the left tail of the sampling distribution 
C)  half in one tail and half in the other 
D)  in the center of the sampling distribution 
A)  entirely in the right tail of the sampling distribution 
B)  entirely in the left tail of the sampling distribution 
C)  half in one tail and half in the other 
D)  in the center of the sampling distribution A

Question 3

You read in a popular new magazine "A group of college women scored significantly higher, on the average, than a group of college men on the specially constructed test of intuitive problem solving."
(a)How is the statistically unsophisticated person likely to interpret the above statement (consider in particular the italicized phrase)?
(b)What does the statement really mean? Answer in terms of what was tested and what was decided.
(c)Is it possible that the difference in means between the women and men was in fact quite small? If so, how could a significant difference be observed?
(d)What additional statistical information would you want in order to evaluate the difference between the women and the men?

Accepted Answer

(a) Difference between the sexes large and "important"
(b)

tested and rejected; conclusion:

(c) yes; very large samples would result in a very small standard error and a large t
(d)

and estimates of the population standard deviations (e.g., s_p).

Question 4

The effect size d is

Accepted Answer

A)  .25 
B)  .75 
C)  .67 
D)  .33 
A)  .25 
B)  .75 
C)  .67 
D)  .33

Question 5

Suppose that    Suppose also that the effect size    Thus,   must equal

Accepted Answer

A)  28 
B)  29 
C)  32.2 
D)  26.4 
A)  28 
B)  29 
C)  32.2 
D)  26.4

Question 6

We wish to compare the marriage counselors from two different clinics with regard to how often couples they have counseled seek a divorce. As many as possible of the couples counseled by each of the counselors are located. The following are the percentages for each counselor of client couples who obtained, or were seeking, a divorce one year after termination of counseling:
   Set up the appropriate statistical hypotheses; perform the test ($\alpha$ = .05); and draw final conclusions.

Accepted Answer

(a) 
 @#IMG-DLM& 
(b)
 @#IMG-DLM& 
(c) r

Question 7

In a two-group experiment, random assignment

Accepted Answer

A)  insures lack of bias in the experiment 
B)  insures lack of bias in the long run 
C)  insures equality of the two groups 
D)  is important solely for statistical reasons 
A)  insures lack of bias in the experiment 
B)  insures lack of bias in the long run 
C)  insures equality of the two groups 
D)  is important solely for statistical reasons

Question 8

The central limit theorem is of assistance for the sampling distribution of

Accepted Answer

A)  single means only 
B)  differences between two means only 
C)  both of the above 
D)  single means to a great extent, and differences between two means to a small extent 
A)  single means only 
B)  differences between two means only 
C)  both of the above 
D)  single means to a great extent, and differences between two means to a small extent

Question 9

The scores from two randomly selected samples from populations A and B are as follows: A: 2, 4,B: 3, 5.The pooled variance estimate,   
 would equal

Accepted Answer

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

Question 10

We are screening drugs for possible use against cancer. We implant 11 laboratory mice with cancer cells. Five of them selected at random are treated with Theron-P. Two months later, detectable tumors are removed from all 11 animals and weighed. The following are the results (in grams):
   
(a) Set up  
  
   and 
 
   . 
(b)Perform the test ($\alpha$ = .05)
(c) Draw final conclusions.

Accepted Answer

(a)
 @#IMG-DLM& (b)
 @#IMG-DLM& 
(c) rej

Question 11

We wish to test the hypothesis of no difference between the means of two independent samples. The first sample consists of 30 cases and the second consists of 20 cases. The number of degrees of freedom for the test is

Accepted Answer

A)  25 
B)  48 
C)  49 
D)  50 
A)  25 
B)  48 
C)  49 
D)  50

Question 12

The makers of Streamer automobiles wish to compare two possible carburetors for use in their larger V-6 model with regard to gasoline consumption. Eight new Streamers with V-6 engines are randomly divided into two groups. One group has Type L carburetors installed and the other, Type M carburetors. The following are the results of standard city mileage tests on the Streamers (in mpg):
   Set up 
   
and   
; perform the test ($\alpha$ = .05), and draw final conclusions.

Accepted Answer

(a)? 
 @#IMG-DLM& 
?
(b)?
 @#IMG-DLM& 
(c)? reject

Question 13

The exact nature of the random sampling distribution of differences between two means is dependent on

Accepted Answer

A)  sample size 
B)    
C)  both of the above 
D)  none of the above 
A)  sample size 
B)    
C)  both of the above 
D)  none of the above

Question 14

To test the null hypothesis of no difference between two means, we calculate the statistic

Accepted Answer

A)    
B) 
  
C)    
D)    
A)    
B) 
  
C)    
D)

Question 15

The variance estimate made by pooling data from two samples is calculated by

Accepted Answer

A)    
B)    
C)    
D)    
A)    
B)    
C)    
D)

Question 16

The test of the difference between two means involves comparison of means of

Accepted Answer

A)  the same variable under the same conditions 
B)  the same variable under different conditions 
C)  different variables under the same conditions 
D)  different variables under different conditions 
A)  the same variable under the same conditions 
B)  the same variable under different conditions 
C)  different variables under the same conditions 
D)  different variables under different conditions

Question 17

As used in most behavioral science experiments, statistical inference procedures do not provide us with

Accepted Answer

A)  the authority to make inferences beyond our particular set of conditions and type of subjects 
B)  a means of accounting for chance sampling variations in our particular sample results 
C)  a means of determining the kinds of results that would be expected as a result of chance factors 
D)  they provide us with all of the above 
A)  the authority to make inferences beyond our particular set of conditions and type of subjects 
B)  a means of accounting for chance sampling variations in our particular sample results 
C)  a means of determining the kinds of results that would be expected as a result of chance factors 
D)  they provide us with all of the above

Question 18

You plan to perform an experiment and conduct a two-tailed test of 
   ($\alpha$ = .05).

Suppose that in fact   
How many times out of 100 repetitions of your experiments would you expect to obtain significant results if you use samples of size:
(a)8(b) 15 (c)45(d)110

Accepted Answer

@#IMG-DLM& approximate answers

Question 19

In testing the difference between two means, the total of sample size is, in general, used most efficiently when

Accepted Answer

A)     and    are as discrepant as possible 
B)    
is 4 times the size of    (or vice versa) 
C)     is 2 times the size    (or vice versa) 
D)    
A)     and    are as discrepant as possible 
B)    
is 4 times the size of    (or vice versa) 
C)     is 2 times the size    (or vice versa) 
D)

Question 20

If some fact of an experiment results in a smaller standard error of the difference between two means than otherwise, this is

Accepted Answer

A)  undesirable, because it will make it less likely to claim a difference when one exists 
B)  undesirable, because it makes it more likely to claim no difference when there is a difference 
C)  desirable, because it makes it more likely to claim a difference when one exists 
D)  desirable, because it makes it less likely to claim a difference when there is none 
A)  undesirable, because it will make it less likely to claim a difference when one exists 
B)  undesirable, because it makes it more likely to claim no difference when there is a difference 
C)  desirable, because it makes it more likely to claim a difference when one exists 
D)  desirable, because it makes it less likely to claim a difference when there is none

The assumption of homogeneity of variance means that

The effect size d is

Suppose that Suppose also that the effect size Thus, must equal

In a two-group experiment, random assignment

The central limit theorem is of assistance for the sampling distribution of

The scores from two randomly selected samples from populations A and B are as follows: A: 2, 4,B: 3, 5.The pooled variance estimate, would equal

We wish to test the hypothesis of no difference between the means of two independent samples. The first sample consists of 30 cases and the second consists of 20 cases. The number of degrees of freedom for the test is

The exact nature of the random sampling distribution of differences between two means is dependent on

To test the null hypothesis of no difference between two means, we calculate the statistic

The variance estimate made by pooling data from two samples is calculated by

The test of the difference between two means involves comparison of means of

As used in most behavioral science experiments, statistical inference procedures do not provide us with

In testing the difference between two means, the total of sample size is, in general, used most efficiently when

If some fact of an experiment results in a smaller standard error of the difference between two means than otherwise, this is

Introduction

Frequency Distributions, Percentiles,

Graphic Representation of Frequency Distributions

Central Tendency

Variability and Standard Z Scores

Standard Scores and the Normal Curve

Correlation

Prediction

Interpretive Aspects of Correlation and Regression

Probability

Random Sampling and Sampling Distributions

Introduction to Statistical Inference: Testing Hypotheses About Single Means Z and T

Interpreting the Results of Hypothesis Testing: Effect Size, Type I and Type II Errors, and Power

Testing for a Difference

Inference About Correlation Coefficients

An Alternative to Hypothesis Testing: Confidence Intervals

Testing for Differences Among Three or More Groups: One-Way Analysis of Variance and Some Alternatives

Factorial Analysis of Variance

Chi-Square and Inference About Frequencies

Some Almost Assumption-Free Tests

Filters

Exam 14: Testing Hypotheses About the Difference Between Two Independent Groups

The assumption of homogeneity of variance means that

The effect size d is

Suppose that Suppose also that the effect size Thus, must equal

In a two-group experiment, random assignment

The central limit theorem is of assistance for the sampling distribution of

The scores from two randomly selected samples from populations A and B are as follows: A: 2, 4,B: 3, 5.The pooled variance estimate, would equal

We wish to test the hypothesis of no difference between the means of two independent samples. The first sample consists of 30 cases and the second consists of 20 cases. The number of degrees of freedom for the test is

The exact nature of the random sampling distribution of differences between two means is dependent on

To test the null hypothesis of no difference between two means, we calculate the statistic

The variance estimate made by pooling data from two samples is calculated by

The test of the difference between two means involves comparison of means of

As used in most behavioral science experiments, statistical inference procedures do not provide us with

You plan to perform an experiment and conduct a two-tailed test of ( α\alphaα = .05). Suppose that in fact How many times out of 100 repetitions of your experiments would you expect to obtain significant results if you use samples of size: (a)8(b) 15 (c)45(d)110

In testing the difference between two means, the total of sample size is, in general, used most efficiently when

If some fact of an experiment results in a smaller standard error of the difference between two means than otherwise, this is

Introduction

Frequency Distributions, Percentiles,

Graphic Representation of Frequency Distributions

Central Tendency

Variability and Standard Z Scores

Standard Scores and the Normal Curve

Correlation

Prediction

Interpretive Aspects of Correlation and Regression

Probability

Random Sampling and Sampling Distributions

Introduction to Statistical Inference: Testing Hypotheses About Single Means Z and T

Interpreting the Results of Hypothesis Testing: Effect Size, Type I and Type II Errors, and Power

Testing for a Difference

Inference About Correlation Coefficients

An Alternative to Hypothesis Testing: Confidence Intervals

Testing for Differences Among Three or More Groups: One-Way Analysis of Variance and Some Alternatives

Factorial Analysis of Variance

Chi-Square and Inference About Frequencies

Some Almost Assumption-Free Tests

Filters