Question 1

Which of the following is consistent with the empirical rule?

Accepted Answer

A) 68% of all scores lie within one standard deviation of the mean. 
B) 95% of all scores lie within two standard deviations of the mean. 
C) 99.7% of all scores lie within three standard deviations of the mean. 
D) all of the above 
A) 68% of all scores lie within one standard deviation of the mean. 
B) 95% of all scores lie within two standard deviations of the mean. 
C) 99.7% of all scores lie within three standard deviations of the mean. 
D) all of the above D

Question 2

A researcher records the number of individual instruments identified by students listening to a piece of classical music.He splits the data into quartiles and reports that students correctly identified 3 instruments at the 25th percentile,5 instruments at the 50th percentile,and 8 instruments at the 75th percentile.What are the IQR and SIQR for these data?

Accepted Answer

A) the IQR is 3;the SIQR is 1.5 
B) the IQR is 2;the SIQR is 1.0 
C) the IQR is 5;the SIQR is 2.5 
D) There is not enough information to answer this question. 
A) the IQR is 3;the SIQR is 1.5 
B) the IQR is 2;the SIQR is 1.0 
C) the IQR is 5;the SIQR is 2.5 
D) There is not enough information to answer this question. C

Question 3

A researcher records the sound (in decibels)during a series of lessons taught by a substitute teacher at a local elementary school.In his study,he found that the sound was 80±6 (M±SD)decibels.Assuming the data are normally distributed,which of the following is an appropriate conclusion?

Accepted Answer

A) 68% of classes were between 68 and 80 decibels. 
B) 5% of classes were louder than 68 decibels. 
C) 95% of classes were between 68 and 92 decibels. 
D) all of the above 
A) 68% of classes were between 68 and 80 decibels. 
B) 5% of classes were louder than 68 decibels. 
C) 95% of classes were between 68 and 92 decibels. 
D) all of the above C

Question 4

The interquartile range and semi-interquartile range are the same measure.

Accepted Answer

A) True 
 B)False

Question 5

Suppose a researcher selects a sample of 16 participants and computes SS = 60.In this example,the standard deviation is 4.

Accepted Answer

A) True 
 B)False

Question 6

Regardless of the number of scores in a distribution,the range only includes ___ score(s)in its calculation.

Accepted Answer

A) one 
B) two 
C) at most two 
D) the average 
A) one 
B) two 
C) at most two 
D) the average

Question 7

A reason for squaring deviations to compute SS in the numerator includes which of the following?

Accepted Answer

A) The sum of the differences of scores from their mean is zero. 
B) The sum of the squared differences of scores from their mean is minimal. 
C) Squaring scores can be corrected easily by square rooting. 
D) all of the above 
A) The sum of the differences of scores from their mean is zero. 
B) The sum of the squared differences of scores from their mean is minimal. 
C) Squaring scores can be corrected easily by square rooting. 
D) all of the above

Question 8

The variance and standard deviation can never be

Accepted Answer

A) zero 
B) negative 
C) smaller than the mean 
D) larger than the mean 
A) zero 
B) negative 
C) smaller than the mean 
D) larger than the mean

Question 9

When the sample variance is computed as SS divided by n,it will underestimate the population variance on average.

Accepted Answer

A) True 
 B)False

Question 10

The range,a measure of variability,

Accepted Answer

A) is the difference between the largest (L)and smallest (S)value in a list of scores 
B) is the most informative when used to describe data sets without outliers 
C) includes only two values in its computation,regardless of the number of scores in a distribution 
D) all of the above 
A) is the difference between the largest (L)and smallest (S)value in a list of scores 
B) is the most informative when used to describe data sets without outliers 
C) includes only two values in its computation,regardless of the number of scores in a distribution 
D) all of the above

Question 11

A researcher computes the computational formula for SS,as finds that ∑x = 22 and ∑x2 = 126.If this is a sample of 4 scores,then what would SS equal using the definitional formula?

Accepted Answer

A) 4 
B) 5 
C) 104 
D) not possible to know because the sample mean is not given 
A) 4 
B) 5 
C) 104 
D) not possible to know because the sample mean is not given

Question 12

The sample variance is:

Accepted Answer

A) an unbiased estimator of the population variance 
B) associated with n - 1 degrees of freedom 
C) computed by dividing SS by df 
D) all of the above 
A) an unbiased estimator of the population variance 
B) associated with n - 1 degrees of freedom 
C) computed by dividing SS by df 
D) all of the above

Question 13

All other things being equal (so assuming that the value of SS never changes),as sample size increases,

Accepted Answer

A) the degrees of freedom for sample variance decrease 
B) the value of sample variance decreases 
C) the value in the numerator for sample variance increases 
D) the value in the denominator for sample variance decreases 
A) the degrees of freedom for sample variance decrease 
B) the value of sample variance decreases 
C) the value in the numerator for sample variance increases 
D) the value in the denominator for sample variance decreases

Question 14

The definitional formula ______ the computational formula for SS.

Accepted Answer

A) estimates 
B) explains 
C) diminishes 
D) equals 
A) estimates 
B) explains 
C) diminishes 
D) equals

Question 15

A main disadvantage of computing a range is that it is a simple and quick measure of variability.

Accepted Answer

A) True 
 B)False

Question 16

The population standard deviation is equal to 10 when SS = 100 and n = 10.

Accepted Answer

A) True 
 B)False

Question 17

Which of the following is an example of a distribution with NO variability?

Accepted Answer

A) scores: 3,5,4,4,5,and 3 
B) scores: 3,3,3,3,33,and 3 
C) scores: 1,2,3,4,5,and 6 
D) scores: 5,5,5,5,5,and 5 
A) scores: 3,5,4,4,5,and 3 
B) scores: 3,3,3,3,33,and 3 
C) scores: 1,2,3,4,5,and 6 
D) scores: 5,5,5,5,5,and 5

Question 18

A researcher computes the following scores: 12,8,14,12,and 10.If these scores were substituted into each formula,the sample variance would be smaller than the population variance.

Accepted Answer

A) True 
 B)False

Question 19

A psychologist treats 16 patients and records the number of sessions required to complete a behavioral therapy treatment for each patient.She computes SS = 800.Assuming the 16 patients constitute all patients under her care (so the population of her patients),what is the standard deviation for these data?

Accepted Answer

A) 53.3 sessions 
B) 50 sessions 
C) 7.1 sessions 
D) 7.3 sessions 
A) 53.3 sessions 
B) 50 sessions 
C) 7.1 sessions 
D) 7.3 sessions

Question 20

A researcher records the following scores for attention during a video game task for two samples.Which sample has the largest standard deviation?
Sample A: 10,12,14,16,and 18
Sample B: 20,24,28,32,and 36

Accepted Answer

A) Sample A 
B) Sample B 
C) Both samples have the same standard deviation. 
A) Sample A 
B) Sample B 
C) Both samples have the same standard deviation.

Which of the following is consistent with the empirical rule?

A researcher records the sound (in decibels)during a series of lessons taught by a substitute teacher at a local elementary school.In his study,he found that the sound was 80±6 (M±SD)decibels.Assuming the data are normally distributed,which of the following is an appropriate conclusion?

The interquartile range and semi-interquartile range are the same measure.

Suppose a researcher selects a sample of 16 participants and computes SS = 60.In this example,the standard deviation is 4.

Regardless of the number of scores in a distribution,the range only includes ___ score(s)in its calculation.

A reason for squaring deviations to compute SS in the numerator includes which of the following?

The variance and standard deviation can never be

When the sample variance is computed as SS divided by n,it will underestimate the population variance on average.

The range,a measure of variability,

A researcher computes the computational formula for SS,as finds that ∑x = 22 and ∑x² = 126.If this is a sample of 4 scores,then what would SS equal using the definitional formula?

The sample variance is:

All other things being equal (so assuming that the value of SS never changes),as sample size increases,

The definitional formula ______ the computational formula for SS.

A main disadvantage of computing a range is that it is a simple and quick measure of variability.

The population standard deviation is equal to 10 when SS = 100 and n = 10.

Which of the following is an example of a distribution with NO variability?

A researcher computes the following scores: 12,8,14,12,and 10.If these scores were substituted into each formula,the sample variance would be smaller than the population variance.

A researcher records the following scores for attention during a video game task for two samples.Which sample has the largest standard deviation? Sample A: 10,12,14,16,and 18 Sample B: 20,24,28,32,and 36

Introduction to Statistics

Summarizing Data: Frequency Distributions in Tables and Graphs

Summarizing Data: Central Tendency

Probability

Probability, Normal Distributions, and Z Scores

Probability and Sampling Distributions

Hypothesis Testing: Significance, Effect Size, and Power

Testing Means: One-Sample and Two-Independent Sample T Tests

Testing Means: Related Samples T Test

Estimation and Confidence Intervals

Analysis of Variance: One-Way Between-Subjects Design

Analysis of Variance: One-Way Within-Subjects Repeated Measures Design

Analysis of Variance: Two-Way Between-Subjects Factorial Design

Correlation

Linear Regression and Multiple Regression

Nonparametric Tests: Chi-Square Tests

Nonparametric Tests: Tests for Ordinal Data

Filters

Exam 4: Summarizing Data: Variability

Which of the following is consistent with the empirical rule?

A researcher records the sound (in decibels)during a series of lessons taught by a substitute teacher at a local elementary school.In his study,he found that the sound was 80±6 (M±SD)decibels.Assuming the data are normally distributed,which of the following is an appropriate conclusion?

The interquartile range and semi-interquartile range are the same measure.

Suppose a researcher selects a sample of 16 participants and computes SS = 60.In this example,the standard deviation is 4.

Regardless of the number of scores in a distribution,the range only includes ___ score(s)in its calculation.

A reason for squaring deviations to compute SS in the numerator includes which of the following?

The variance and standard deviation can never be

When the sample variance is computed as SS divided by n,it will underestimate the population variance on average.

The range,a measure of variability,

A researcher computes the computational formula for SS,as finds that ∑x = 22 and ∑x2 = 126.If this is a sample of 4 scores,then what would SS equal using the definitional formula?

The sample variance is:

All other things being equal (so assuming that the value of SS never changes),as sample size increases,

The definitional formula ______ the computational formula for SS.

A main disadvantage of computing a range is that it is a simple and quick measure of variability.

The population standard deviation is equal to 10 when SS = 100 and n = 10.

Which of the following is an example of a distribution with NO variability?

A researcher computes the following scores: 12,8,14,12,and 10.If these scores were substituted into each formula,the sample variance would be smaller than the population variance.

A researcher records the following scores for attention during a video game task for two samples.Which sample has the largest standard deviation? Sample A: 10,12,14,16,and 18 Sample B: 20,24,28,32,and 36

Introduction to Statistics

Summarizing Data: Frequency Distributions in Tables and Graphs

Summarizing Data: Central Tendency

Probability

Probability, Normal Distributions, and Z Scores

Probability and Sampling Distributions

Hypothesis Testing: Significance, Effect Size, and Power

Testing Means: One-Sample and Two-Independent Sample T Tests

Testing Means: Related Samples T Test

Estimation and Confidence Intervals

Analysis of Variance: One-Way Between-Subjects Design

Analysis of Variance: One-Way Within-Subjects Repeated Measures Design

Analysis of Variance: Two-Way Between-Subjects Factorial Design

Correlation

Linear Regression and Multiple Regression

Nonparametric Tests: Chi-Square Tests

Nonparametric Tests: Tests for Ordinal Data

Filters

A researcher computes the computational formula for SS,as finds that ∑x = 22 and ∑x² = 126.If this is a sample of 4 scores,then what would SS equal using the definitional formula?