Question 1

According to Cohen's convention, a value of _____ is a small effect size.

Accepted Answer

A)  0.2 
B)  0.5 
C)  0.8 
D)  340 
A)  0.2 
B)  0.5 
C)  0.8 
D)  340

Question 2

Hypothesis testing tells:

Accepted Answer

A)  what the size of an effect is. 
B)  which group differences are of practical importance. 
C)  whether two distributions overlap at all. 
D)  what results are significant, but no details regarding significant results. 
A)  what the size of an effect is. 
B)  which group differences are of practical importance. 
C)  whether two distributions overlap at all. 
D)  what results are significant, but no details regarding significant results.

Question 3

An overlap between two distributions of approximately 39 percent is likely to result in a(n) _____ effect size.

Accepted Answer

A)  small 
B)  medium 
C)  large 
D)  unconventional 
A)  small 
B)  medium 
C)  large 
D)  unconventional

Question 4

What falls within the 95 percent confidence interval?

Accepted Answer

A)  all the means we would expect to obtain 5 percent of the time when repeatedly sampling from a population 
B)  all the means we would expect to obtain 95 percent of the time when repeatedly sampling from a population 
C)  the true population mean 
D)  the null hypothesis population mean 
A)  all the means we would expect to obtain 5 percent of the time when repeatedly sampling from a population 
B)  all the means we would expect to obtain 95 percent of the time when repeatedly sampling from a population 
C)  the true population mean 
D)  the null hypothesis population mean

Question 5

When comparing the difference between means for two distributions, what happens to the effect size if the variability within each distribution becomes smaller?

Accepted Answer

A)  There is no change in the effect size. 
B)  The effect size decreases. 
C)  The effect size increases. 
D)  It is not possible to find based the information provided. 
A)  There is no change in the effect size. 
B)  The effect size decreases. 
C)  The effect size increases. 
D)  It is not possible to find based the information provided.

Question 6

Confidence in a point estimate _____, whereas confidence in an interval estimate _____.

Accepted Answer

A)  is very high; is very low 
B)  is based on the alpha level used; is based on the margin of error calculated 
C)  cannot be articulated; is directly related to the size of the interval constructed 
D)  is very low; is very high 
A)  is very high; is very low 
B)  is based on the alpha level used; is based on the margin of error calculated 
C)  cannot be articulated; is directly related to the size of the interval constructed 
D)  is very low; is very high

Question 7

Increasing N to increase statistical power is considered a suspect practice by statisticians.

Accepted Answer

A) True 
 B)False

Question 8

Which of the following does NOT increase statistical power?

Accepted Answer

A)  increasing alpha 
B)  using a one-tailed hypothesis 
C)  decreasing sample size 
D)  exaggerating differences between levels of the independent variable 
A)  increasing alpha 
B)  using a one-tailed hypothesis 
C)  decreasing sample size 
D)  exaggerating differences between levels of the independent variable

Question 9

Imagine that a study of memory and aging finds that younger participants correctly recall 55 percent of studied words, older participants correctly recall 42 percent of studied words, and the size of this effect is Cohen's d = 0.49.According to Cohen's conventions for interpreting d, this effect is:

Accepted Answer

A)  small. 
B)  medium. 
C)  large. 
D)  so small as to be considered virtually no effect. 
A)  small. 
B)  medium. 
C)  large. 
D)  so small as to be considered virtually no effect.

Question 10

If the population mean falls within the confidence interval, this means it is plausible that the sample comes from the null hypothesized population.

Accepted Answer

A) True 
 B)False

Question 11

Statistical power can be enhanced by decreasing the standard deviation in the sample.This can be accomplished by all of these EXCEPT:

Accepted Answer

A)  working with a biased sample. 
B)  using a more reliable measure. 
C)  sampling a more homogeneous group. 
D)  working with a narrower, less variable, distribution of scores. 
A)  working with a biased sample. 
B)  using a more reliable measure. 
C)  sampling a more homogeneous group. 
D)  working with a narrower, less variable, distribution of scores.

Question 12

If the population mean falls within the 95 percent confidence interval, one should reject the null hypothesis.

Accepted Answer

A) True 
 B)False

Question 13

In calculating confidence intervals in a z distribution, start by finding the z scores centered around the:

Accepted Answer

A)  population mean. 
B)  sample mean. 
C)  standard error. 
D)  sum of squares. 
A)  population mean. 
B)  sample mean. 
C)  standard error. 
D)  sum of squares.

Question 14

The interval estimate for two values overlaps.What might this indicate?

Accepted Answer

A)  Both points may actually have the same value in the general population, although one appears slightly higher, possibly due to uncertainty of the sample. 
B)  The range between the two points absolutely represents a genuine difference in the general population. 
C)  Both points must be equal if there is any overlap among their interval estimates because of error in estimating the population from a sample. 
D)  There is no way to tell if the difference between the two points is genuine. 
A)  Both points may actually have the same value in the general population, although one appears slightly higher, possibly due to uncertainty of the sample. 
B)  The range between the two points absolutely represents a genuine difference in the general population. 
C)  Both points must be equal if there is any overlap among their interval estimates because of error in estimating the population from a sample. 
D)  There is no way to tell if the difference between the two points is genuine.

Question 15

The minimum acceptable level of estimated power for a study is:

Accepted Answer

A)  0.95. 
B)  0.80. 
C)  0.45. 
D)  0.10. 
A)  0.95. 
B)  0.80. 
C)  0.45. 
D)  0.10.

Question 16

Increasing the number of scores in a sample from 10 to 20 increases the width of a confidence interval to estimate the population mean.(Assume that all other factors are held constant.)

Accepted Answer

A) True 
 B)False

Question 17

An interval estimate is based on a sample statistic and provides a range of plausible values for the population parameter.

Accepted Answer

A) True 
 B)False

Question 18

Which of the following does NOT increase statistical power?

Accepted Answer

A)  increasing alpha 
B)  using a two-tailed hypothesis 
C)  increasing sample size 
D)  exaggerating differences between levels of the independent variable 
A)  increasing alpha 
B)  using a two-tailed hypothesis 
C)  increasing sample size 
D)  exaggerating differences between levels of the independent variable

Question 19

When Cohen's d is large (based on Cohen's conventions), the amount of overlap between the two distributions being compared is _____ percent.

Accepted Answer

A)  75 
B)  53 
C)  15 
D)  0 
A)  75 
B)  53 
C)  15 
D)  0

Question 20

Effect sizes are calculated _____ the study.

Accepted Answer

A)  during 
B)  before 
C)  after 
D)  throughout 
A)  during 
B)  before 
C)  after 
D)  throughout

According to Cohen's convention, a value of _____ is a small effect size.

Hypothesis testing tells:

An overlap between two distributions of approximately 39 percent is likely to result in a(n) _____ effect size.

What falls within the 95 percent confidence interval?

When comparing the difference between means for two distributions, what happens to the effect size if the variability within each distribution becomes smaller?

Confidence in a point estimate _, whereas confidence in an interval estimate _.

Increasing N to increase statistical power is considered a suspect practice by statisticians.

Which of the following does NOT increase statistical power?

Imagine that a study of memory and aging finds that younger participants correctly recall 55 percent of studied words, older participants correctly recall 42 percent of studied words, and the size of this effect is Cohen's d = 0.49.According to Cohen's conventions for interpreting d, this effect is:

If the population mean falls within the confidence interval, this means it is plausible that the sample comes from the null hypothesized population.

Statistical power can be enhanced by decreasing the standard deviation in the sample.This can be accomplished by all of these EXCEPT:

If the population mean falls within the 95 percent confidence interval, one should reject the null hypothesis.

In calculating confidence intervals in a z distribution, start by finding the z scores centered around the:

The interval estimate for two values overlaps.What might this indicate?

The minimum acceptable level of estimated power for a study is:

Increasing the number of scores in a sample from 10 to 20 increases the width of a confidence interval to estimate the population mean.(Assume that all other factors are held constant.)

An interval estimate is based on a sample statistic and provides a range of plausible values for the population parameter.

Which of the following does NOT increase statistical power?

When Cohen's d is large (based on Cohen's conventions), the amount of overlap between the two distributions being compared is _____ percent.

Effect sizes are calculated _____ the study.

An Introduction to Statistics and Research Design

Frequency Distributions

Visual Displays of Data

Central Tendency and Variability

Sampling and Probability

The Normal Curve, Standardization and Z Scores

Hypothesis Testing With Z Tests

The Single-Sample T Test

The Paired-Samples T Test

The Independent-Samples T Test

One-Way Between-Groups Anova

One-Way Within-Groups Anova

Two-Way Between-Groups Anova

Correlation

Regression

Chi-Square Tess

Choosing and Reporting Statistics

Filters

Exam 8: Confidence Intervals, Effect Size, and Statistical Power

According to Cohen's convention, a value of _____ is a small effect size.

Hypothesis testing tells:

An overlap between two distributions of approximately 39 percent is likely to result in a(n) _____ effect size.

What falls within the 95 percent confidence interval?

When comparing the difference between means for two distributions, what happens to the effect size if the variability within each distribution becomes smaller?

Confidence in a point estimate _____, whereas confidence in an interval estimate _____.

Increasing N to increase statistical power is considered a suspect practice by statisticians.

Which of the following does NOT increase statistical power?

If the population mean falls within the confidence interval, this means it is plausible that the sample comes from the null hypothesized population.

Statistical power can be enhanced by decreasing the standard deviation in the sample.This can be accomplished by all of these EXCEPT:

If the population mean falls within the 95 percent confidence interval, one should reject the null hypothesis.

In calculating confidence intervals in a z distribution, start by finding the z scores centered around the:

The interval estimate for two values overlaps.What might this indicate?

The minimum acceptable level of estimated power for a study is:

Increasing the number of scores in a sample from 10 to 20 increases the width of a confidence interval to estimate the population mean.(Assume that all other factors are held constant.)

An interval estimate is based on a sample statistic and provides a range of plausible values for the population parameter.

Which of the following does NOT increase statistical power?

When Cohen's d is large (based on Cohen's conventions), the amount of overlap between the two distributions being compared is _____ percent.

Effect sizes are calculated _____ the study.

An Introduction to Statistics and Research Design

Frequency Distributions

Visual Displays of Data

Central Tendency and Variability

Sampling and Probability

The Normal Curve, Standardization and Z Scores

Hypothesis Testing With Z Tests

The Single-Sample T Test

The Paired-Samples T Test

The Independent-Samples T Test

One-Way Between-Groups Anova

One-Way Within-Groups Anova

Two-Way Between-Groups Anova

Correlation

Regression

Chi-Square Tess

Choosing and Reporting Statistics

Filters

Confidence in a point estimate _, whereas confidence in an interval estimate _.