Question 1

How could a researcher interpret an r2 value of .35?

Accepted Answer

A)   .35% of the variance in one variable is explained by another variable.
B)   3.5% of the variance in one variable is explained by another variable.
C)   35% of the variance in one variable is explained by another variable.
D)   65% of the variance in one variable is explained by another variable.

Question 2

Type I errors occur as the result of chance factors.

Accepted Answer

A) True 
 B)False

Question 3

The probability of making a type II error is ______.

Accepted Answer

A)   .05
B)   1 - α
C)   .95
D)   none of these

Question 4

In airport security screening, ______ errors occur when the screening device ______ when in fact ______.

Accepted Answer

A)   type I; beeps; it should not
B)   type I; does not beep; it should
C)   type II; beeps; it should not
D)   type II; beeps; it should

Question 5

The probability of making a ______ error is equal to ______.

Accepted Answer

A)   type I; 1 - β
B)   type II; 0
C)   type II; α
D)   type II; β

Question 6

For which of these strategies used to reduce the probability of type II error are pragmatic concerns such as time and cost most relevant?

Accepted Answer

A)   using a directional (one-tailed)  rather than non-directional (two-tailed)  alternative hypothesis
B)   increasing sample size
C)   making it harder to reject the null hypothesis
D)   changing alpha

Question 7

A type II error means that a researcher has ______.

Accepted Answer

A)   correctly concluded that an effect does not exist
B)   correctly concluded that an effect exists
C)   falsely concluded that an effect does not exist
D)   falsely concluded that an effect exists

Question 8

Calculate the r2 statistic for t = 2.56 and two groups of 20 individuals each.

Accepted Answer

A)   .06
B)   .15
C)   .25
D)   .27

Question 9

Which of the following would be considered a 'large' effect size according to Cohen?

Accepted Answer

A)   r2 = .21
B)   r2 = .02
C)   r2 = .05
D)   r2 = .12

Question 10

A type I error occurs when researchers make the decision to ______ when they ______.

Accepted Answer

A)   reject the null hypothesis; should
B)   reject the null hypothesis; should not
C)   reject the alternative hypothesis; should not
D)   not reject the null hypothesis; should not

Question 11

One way to reduce the probability of making a type I error is to ______.

Accepted Answer

A)   make it easier to reject the null hypothesis
B)   increase sample size
C)   increase alpha
D)   lower alpha

Question 12

A type II error occurs when a researcher says an effect ______ when it in fact ______.

Accepted Answer

A)   exists; does
B)   exists; does not
C)   does not exist; does
D)   does not exist; does not

Question 13

Which of these strategies is MOST commonly used to decrease type II error?

Accepted Answer

A)   using a non-directional (two-tailed)  alternative hypothesis (H1) 
B)   using a directional (one-tailed)  null hypothesis (H0) 
C)   increasing sample size
D)   lowering alpha

Question 14

An r2 = .01 is considered a 'large' effect size according to Cohen.

Accepted Answer

A) True 
 B)False

Question 15

Which of these strategies is most commonly used to reduce the probability of type II error?

Accepted Answer

A)   use a non-directional (two-tailed)  instead of a directional (one-tailed)  alternative hypothesis
B)   never conclude an effect exists regardless of the evidence
C)   increase sample size
D)   lower alpha

Question 16

Which of these strategies is MOST commonly used to decrease type I error?

Accepted Answer

A)   using a directional alternative hypothesis
B)   lowering alpha
C)   increasing sample size
D)   increasing alpha

Question 17

A type I error only affects the research community.

Accepted Answer

A) True 
 B)False

Question 18

An r2 = .86 is considered a 'large' effect size according to Cohen.

Accepted Answer

A) True 
 B)False

Question 19

Which statistic is an estimate of the magnitude of the difference between the means of two groups measured in standard deviation units?

Accepted Answer

A)   r2
B)   t2
C)   Cohen's d
D)   β

Question 20

When the within-group variability in a study is small, the likelihood of rejecting the null hypothesis is ______.

Accepted Answer

A)   smaller
B)   not changed
C)   larger
D)   the same

Exam 10: Errors in Hypothesis Testing, Statistical Power, and Effect Size

A type II error means that a researcher has ______.

Correct AnswerverifiedShow Answer

A type I error occurs when researchers make the decision to ______ when they ______.

Correct AnswerverifiedShow Answer

One way to reduce the probability of making a type I error is to ______.

Correct AnswerverifiedShow Answer

In airport security screening, ______ errors occur when the screening device ______ when in fact ______.

Correct AnswerverifiedShow Answer

Which of these strategies is MOST commonly used to decrease type I error?

Correct AnswerverifiedShow Answer

Which of these strategies is most commonly used to reduce the probability of type II error?

Correct AnswerverifiedShow Answer

A type I error only affects the research community.

Correct AnswerverifiedShow Answer

Which statistic is an estimate of the magnitude of the difference between the means of two groups measured in standard deviation units?

Correct AnswerverifiedShow Answer

The probability of making a ______ error is equal to ______.

Correct AnswerverifiedShow Answer

The probability of making a type II error is ______.

Correct AnswerverifiedShow Answer

How could a researcher interpret an r2 value of .35?

Correct AnswerverifiedShow Answer

A type II error occurs when a researcher says an effect ______ when it in fact ______.

Correct AnswerverifiedShow Answer

An r2 = .01 is considered a 'large' effect size according to Cohen.

Correct AnswerverifiedShow Answer

Calculate the r2 statistic for t = 2.56 and two groups of 20 individuals each.

Correct AnswerverifiedShow Answer

When the within-group variability in a study is small, the likelihood of rejecting the null hypothesis is ______.

Correct AnswerverifiedShow Answer

Which of the following would be considered a 'large' effect size according to Cohen?

Correct AnswerverifiedShow Answer

An r2 = .86 is considered a 'large' effect size according to Cohen.

Correct AnswerverifiedShow Answer

For which of these strategies used to reduce the probability of type II error are pragmatic concerns such as time and cost most relevant?

Correct AnswerverifiedShow Answer

Type I errors occur as the result of chance factors.

Correct AnswerverifiedShow Answer

Which of these strategies is MOST commonly used to decrease type II error?

Correct AnswerverifiedShow Answer

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A type I error occurs when researchers make the decision to when they .

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In airport security screening, errors occur when the screening device when in fact __.

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The probability of making a error is equal to .

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How could a researcher interpret an r² value of .35?

Correct Answer
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A type II error occurs when a researcher says an effect when it in fact .

Correct Answer
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An r² = .01 is considered a 'large' effect size according to Cohen.

Correct Answer
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Calculate the r² statistic for t = 2.56 and two groups of 20 individuals each.

Correct Answer
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Correct Answer
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Correct Answer
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An r² = .86 is considered a 'large' effect size according to Cohen.

Correct Answer
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