Question 1

The degrees of freedom for the sample variance

Accepted Answer

A) are equal to the sample size 
B) are equal to the sample size minus one 
C) can vary between - $\infty$ and +   
D) both B and C 
A) are equal to the sample size 
B) are equal to the sample size minus one 
C) can vary between - $\infty$ and +   
D) both B and C

Question 2

A researcher records the following scores on a working memory quiz for two samples.Which sample has the largest standard deviation?
Sample A: 2,3,4,5,6,7,and 8
Sample B: 4,5,6,7,8,9,and 10

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.

Question 3

A researcher records the following motor assessment scores for two samples of athletes.Which sample has the largest standard deviation?
Sample A: 8,10,12,15,and 18
Sample B: 16,18,20,23,and 26

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.

Question 4

A researcher records the following data: 4,4,4,4,and 3.How would you describe the variability of these data?

Accepted Answer

A) It is equal to zero because scores are approximately the same. 
B) It is negative because 3 is less than the other scores in the distribution. 
C) It is very small (close to 0)because scores are approximately the same. 
D) It is very large (much greater than 0)because 3 is an outlier in the data. 
A) It is equal to zero because scores are approximately the same. 
B) It is negative because 3 is less than the other scores in the distribution. 
C) It is very small (close to 0)because scores are approximately the same. 
D) It is very large (much greater than 0)because 3 is an outlier in the data.

Question 5

The empirical rule states that all scores will fall within 3 standard deviations of the mean.

Accepted Answer

A) True 
 B)False

Question 6

Fractiles are ways that data can be divided into two or more equal parts.An example of a fractile includes

Accepted Answer

A) the median 
B) quartiles 
C) percentiles 
D) all of the above 
A) the median 
B) quartiles 
C) percentiles 
D) all of the above

Question 7

A researcher measures the number of trials it takes two samples of participants to master a new task.In both samples,SS = 240.Sample A consisted of 12 participants and Sample B consisted of 18 participants.Which sample is associated with the largest variance?

Accepted Answer

A) Sample A 
B) Sample B 
C) Both samples have the same variance. 
D) There is not enough information to answer this question. 
A) Sample A 
B) Sample B 
C) Both samples have the same variance. 
D) There is not enough information to answer this question.

Question 8

A researcher records the number of classroom interruptions during each of two class sessions.Which session has the largest standard deviation?
Session A: 12,15,18,24,and 30
Session B: 8,10,12,16,and 20

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.

Question 9

How is the sample variance computed differently from the population variance?

Accepted Answer

A) only one formula includes a computation for SS 
B) the calculation in the numerator is different 
C) the calculation in the denominator is different 
D) both B and C 
A) only one formula includes a computation for SS 
B) the calculation in the numerator is different 
C) the calculation in the denominator is different 
D) both B and C

Question 10

Which of the following is a property of the standard deviation?

Accepted Answer

A) The standard deviation varies between - $\infty$ and +   . 
B) The standard deviation is used to describe qualitative variables. 
C) Multiplying each score times the same constant will change the standard deviation by that constant. 
D) Adding the same constant to each score will change the standard deviation by that constant. 
A) The standard deviation varies between - $\infty$ and +   . 
B) The standard deviation is used to describe qualitative variables. 
C) Multiplying each score times the same constant will change the standard deviation by that constant. 
D) Adding the same constant to each score will change the standard deviation by that constant.

Question 11

A researcher decides to split scores on an exam into quartiles.She determines that a score of 64 is at the 25th percentile,a score of 74 is at the 50th percentile,and a score of 80 is at the 75th percentile.What is the interquartile range (IQR)for these data?

Accepted Answer

A) 16 
B) 10 
C) 6 
D) There is not enough information to answer this question. 
A) 16 
B) 10 
C) 6 
D) There is not enough information to answer this question.

Question 12

The sum of the squared deviations of scores from their mean

Accepted Answer

A) is computed the same for samples and populations 
B) is computed by squaring each deviation to avoid a zero solution in the numerator 
C) is the numerator for the sample variance and population variance 
D) all of the above 
A) is computed the same for samples and populations 
B) is computed by squaring each deviation to avoid a zero solution in the numerator 
C) is the numerator for the sample variance and population variance 
D) all of the above

Question 13

A(n)________ is a sample statistic that equals a population parameter on average.

Accepted Answer

A) biased estimator 
B) degrees of freedom 
C) unbiased estimator 
D) sum of squares 
A) biased estimator 
B) degrees of freedom 
C) unbiased estimator 
D) sum of squares

Question 14

Why is it important to divide by df to compute sample variance?

Accepted Answer

A) doing so makes the sample variance an unbiased estimator of the population variance 
B) doing so ensures that the value for sample variance varies between 0 and 1 
C) doing so minimizes the likelihood that the sample variance will be a negative value 
D) it is not important;dividing by df is optional 
A) doing so makes the sample variance an unbiased estimator of the population variance 
B) doing so ensures that the value for sample variance varies between 0 and 1 
C) doing so minimizes the likelihood that the sample variance will be a negative value 
D) it is not important;dividing by df is optional

Question 15

If SS = 50 for a data set of 10 scores in a population,then the standard deviation is equal to 5.0.

Accepted Answer

A) True 
 B)False

Question 16

A researcher reports that the time (in minutes)it takes children who are "picky eaters" to finish their vegetables is negatively skewed,with children finishing their vegetables in 4.2±1.0 (M±SD)minutes.Based on Chebyshev's theorem,we can conclude that

Accepted Answer

A) 68% of children finished their vegetables in 3.2 to 5.2 minutes. 
B) 50% of children finished their vegetables in at least 3.2 minutes. 
C) 99.7% of children finished their vegetables in 2.2 to 6.2 minutes. 
D) At least 89% of children finished their vegetables in 1.2 to 7.2 minutes. 
A) 68% of children finished their vegetables in 3.2 to 5.2 minutes. 
B) 50% of children finished their vegetables in at least 3.2 minutes. 
C) 99.7% of children finished their vegetables in 2.2 to 6.2 minutes. 
D) At least 89% of children finished their vegetables in 1.2 to 7.2 minutes.

Question 17

An interquartile range removes

Accepted Answer

A) the top and bottom 25% of scores in a distribution before calculating range 
B) scores above only the 75th percentile before calculating range 
C) scores below only the 25th percentile before calculating range 
D) all of the above 
A) the top and bottom 25% of scores in a distribution before calculating range 
B) scores above only the 75th percentile before calculating range 
C) scores below only the 25th percentile before calculating range 
D) all of the above

Question 18

A researcher records a sample of 30 exam scores and finds that the population mean for these data is larger than the sample variance.Is this possible?

Accepted Answer

A) yes,the population variance is usually larger than the sample variance 
B) no,the population variance will only be larger when at least 50 scores are recorded 
C) no,the sample variance will be larger because SS is divided by degrees of freedom in the denominator of the variance formula 
D) not possible to know because the scores are not given 
A) yes,the population variance is usually larger than the sample variance 
B) no,the population variance will only be larger when at least 50 scores are recorded 
C) no,the sample variance will be larger because SS is divided by degrees of freedom in the denominator of the variance formula 
D) not possible to know because the scores are not given

Question 19

Which of the following values is NOT needed to compute sample variance using the computational formula,but is needed to compute the definitional formula?

Accepted Answer

A) sample mean 
B) scores (x) 
C) sample size 
D) degrees of freedom 
A) sample mean 
B) scores (x) 
C) sample size 
D) degrees of freedom

Question 20

A researcher records the following scores for an Olympic gymnast following her routine: 9.9,9.8,9.6,9.5,9.7,9.1,8.9,and 9.8.What is the range for the scores?

Accepted Answer

A) 1.0 (9.9 to 8.9) 
B) 0.3 (9.8 to 9.5) 
C) 0.5 (9.6 to 9.1) 
D) It is not possible to compute a range with an even number of scores. 
A) 1.0 (9.9 to 8.9) 
B) 0.3 (9.8 to 9.5) 
C) 0.5 (9.6 to 9.1) 
D) It is not possible to compute a range with an even number of scores.

The degrees of freedom for the sample variance

A researcher records the following scores on a working memory quiz for two samples.Which sample has the largest standard deviation? Sample A: 2,3,4,5,6,7,and 8 Sample B: 4,5,6,7,8,9,and 10

A researcher records the following motor assessment scores for two samples of athletes.Which sample has the largest standard deviation? Sample A: 8,10,12,15,and 18 Sample B: 16,18,20,23,and 26

A researcher records the following data: 4,4,4,4,and 3.How would you describe the variability of these data?

The empirical rule states that all scores will fall within 3 standard deviations of the mean.

Fractiles are ways that data can be divided into two or more equal parts.An example of a fractile includes

A researcher measures the number of trials it takes two samples of participants to master a new task.In both samples,SS = 240.Sample A consisted of 12 participants and Sample B consisted of 18 participants.Which sample is associated with the largest variance?

A researcher records the number of classroom interruptions during each of two class sessions.Which session has the largest standard deviation? Session A: 12,15,18,24,and 30 Session B: 8,10,12,16,and 20

How is the sample variance computed differently from the population variance?

Which of the following is a property of the standard deviation?

A researcher decides to split scores on an exam into quartiles.She determines that a score of 64 is at the 25th percentile,a score of 74 is at the 50th percentile,and a score of 80 is at the 75th percentile.What is the interquartile range (IQR)for these data?

The sum of the squared deviations of scores from their mean

A(n)________ is a sample statistic that equals a population parameter on average.

Why is it important to divide by df to compute sample variance?

If SS = 50 for a data set of 10 scores in a population,then the standard deviation is equal to 5.0.

A researcher reports that the time (in minutes)it takes children who are "picky eaters" to finish their vegetables is negatively skewed,with children finishing their vegetables in 4.2±1.0 (M±SD)minutes.Based on Chebyshev's theorem,we can conclude that

An interquartile range removes

A researcher records a sample of 30 exam scores and finds that the population mean for these data is larger than the sample variance.Is this possible?

Which of the following values is NOT needed to compute sample variance using the computational formula,but is needed to compute the definitional formula?

A researcher records the following scores for an Olympic gymnast following her routine: 9.9,9.8,9.6,9.5,9.7,9.1,8.9,and 9.8.What is the range for the scores?

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

The degrees of freedom for the sample variance

A researcher records the following scores on a working memory quiz for two samples.Which sample has the largest standard deviation? Sample A: 2,3,4,5,6,7,and 8 Sample B: 4,5,6,7,8,9,and 10

A researcher records the following motor assessment scores for two samples of athletes.Which sample has the largest standard deviation? Sample A: 8,10,12,15,and 18 Sample B: 16,18,20,23,and 26

A researcher records the following data: 4,4,4,4,and 3.How would you describe the variability of these data?

The empirical rule states that all scores will fall within 3 standard deviations of the mean.

Fractiles are ways that data can be divided into two or more equal parts.An example of a fractile includes

A researcher measures the number of trials it takes two samples of participants to master a new task.In both samples,SS = 240.Sample A consisted of 12 participants and Sample B consisted of 18 participants.Which sample is associated with the largest variance?

A researcher records the number of classroom interruptions during each of two class sessions.Which session has the largest standard deviation? Session A: 12,15,18,24,and 30 Session B: 8,10,12,16,and 20

How is the sample variance computed differently from the population variance?

Which of the following is a property of the standard deviation?

A researcher decides to split scores on an exam into quartiles.She determines that a score of 64 is at the 25th percentile,a score of 74 is at the 50th percentile,and a score of 80 is at the 75th percentile.What is the interquartile range (IQR)for these data?

The sum of the squared deviations of scores from their mean

A(n)________ is a sample statistic that equals a population parameter on average.

Why is it important to divide by df to compute sample variance?

If SS = 50 for a data set of 10 scores in a population,then the standard deviation is equal to 5.0.

A researcher reports that the time (in minutes)it takes children who are "picky eaters" to finish their vegetables is negatively skewed,with children finishing their vegetables in 4.2±1.0 (M±SD)minutes.Based on Chebyshev's theorem,we can conclude that

An interquartile range removes

A researcher records a sample of 30 exam scores and finds that the population mean for these data is larger than the sample variance.Is this possible?

Which of the following values is NOT needed to compute sample variance using the computational formula,but is needed to compute the definitional formula?

A researcher records the following scores for an Olympic gymnast following her routine: 9.9,9.8,9.6,9.5,9.7,9.1,8.9,and 9.8.What is the range for the scores?

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