Question 1

If all scores in a distribution are negative values,then the standard deviation will also be a negative value.

Accepted Answer

A) True 
 B)False

Question 2

The degrees of freedom for sample variance are equal to N.

Accepted Answer

A) True 
 B)False

Question 3

The variance and standard deviation can never be

Accepted Answer

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

Question 4

Measures of variability can range in value from

Accepted Answer

A)  -$\infty$ to +$\infty$ 
B)  0 to +$\infty$ 
C)  It depends on whether the variability is positive or negative. 
D)  It depends on the value of the mean for a given distribution.

Question 5

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

Question 6

On average,the sample variance will be equal to the population variance only when dividing SS by df.

Accepted Answer

A) True 
 B)False

Question 7

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

Question 8

A main disadvantage of computing a range is that it takes into consideration only two values regardless of the number of scores in a distribution.

Accepted Answer

A) True 
 B)False

Question 9

Multiplying or dividing each score using the same constant will not change the standard deviation.

Accepted Answer

A) True 
 B)False

Question 10

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.

Question 11

The SIQR can be defined as

Accepted Answer

A)  the range of a distribution divided in half. 
B)  the IQR of a distribution plus the range. 
C)  a measure of half the distance between Q3 and Q1. 
D)  all of these.

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 these.

Question 13

The definitional formula ______ the computational formula for SS.

Accepted Answer

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

Question 14

The computational formula for the variance requires that you know the value of the mean.

Accepted Answer

A) True 
 B)False

Question 15

A researcher measures the time (in seconds)it takes a sample of 26 participants to respond to a stimulus presented on a computer screen.The standard deviation for response times is 6.In this example,what is the value for SS?

Accepted Answer

A)  36 
B)  150 
C)  900 
D)  There is not enough information to answer this question.

Question 16

Suppose a researcher selects a sample of 19 participants and computes SS = 162.In this example,the standard deviation is 3.

Accepted Answer

A) True 
 B)False

Question 17

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 18

As a general rule,an interquartile range is a better estimate of variability than the IQR.

Accepted Answer

A) True 
 B)False

Question 19

Suppose a researcher observes a population of 12 people and computes SS = 192.In this example,the standard deviation is 4.

Accepted Answer

A) True 
 B)False

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.

Exam 4: Summarizing Data: Variability

If all scores in a distribution are negative values,then the standard deviation will also be a negative value.

The degrees of freedom for sample variance are equal to N.

The variance and standard deviation can never be

Measures of variability can range in value from

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

On average,the sample variance will be equal to the population variance only when dividing SS by df.

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

A main disadvantage of computing a range is that it takes into consideration only two values regardless of the number of scores in a distribution.

Multiplying or dividing each score using the same constant will not change the standard deviation.

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?

The SIQR can be defined as

The sum of the squared deviations of scores from their mean

The definitional formula ______ the computational formula for SS.

The computational formula for the variance requires that you know the value of the mean.

A researcher measures the time (in seconds) it takes a sample of 26 participants to respond to a stimulus presented on a computer screen.The standard deviation for response times is 6.In this example,what is the value for SS?

Suppose a researcher selects a sample of 19 participants and computes SS = 162.In this example,the standard deviation is 3.

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

As a general rule,an interquartile range is a better estimate of variability than the IQR.

Suppose a researcher observes a population of 12 people and computes SS = 192.In this example,the standard deviation is 4.

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