Question 1

The variance and standard deviation indicate how much the scores are spread out around

Accepted Answer

A) the range. 
B) the mean. 
C) the median. 
D) the deviation.

Question 2

is the symbol for

Accepted Answer

A) population variance. 
B) sample variance. 
C) population standard deviation. 
D) sample standard deviation.

Question 3

For the following data set,calculate the sample variance. 1.72,4.01,2.55,0.67,1.93,2.05,2.69,3.13,1.22,3.84

Accepted Answer

A) 1.0243 
B) 1.0492 
C) 1.0797 
D) 1.1659

Question 4

What is the estimated population standard deviation  of the following data?

Accepted Answer

A) 1.83 
B) 3.36 
C) 3.16 
D) 1.78

Question 5

What do  ,  ,and  have in common?

Accepted Answer

A) All are forms of standardized variance. 
B) All are forms of standard deviation. 
C) All are forms of variance. 
D) All represent the location of a set of scores.

Question 6

A program evaluator for a large school district wants to study intelligence in the elementary schools.She randomly selects one classroom at each grade level in each elementary school and administers an intelligence test to the children in those classrooms.In order to find out which school has the most consistent intelligence level,which of the following should she calculate for each school?

Accepted Answer

A) The mean 
B) The standard deviation 
C) The median 
D) The range

Question 7

If a sample has a small standard deviation,we can say that the scores in the sample are

Accepted Answer

A) variable. 
B) small. 
C) extreme. 
D) consistent.

Question 8

Which of the following studies shows the strongest relationship between the independent and dependent variables?

Accepted Answer

A) Study A 
B) Study B 
C) Study C 
D) Study D

Question 9

The quantity N F1F1F1S1F1F1F10 1 has a special name.It is known as the

Accepted Answer

A) unbiased estimate. 
B) biased estimate. 
C) degrees of freedom. 
D) freedom of variation.

Question 10

Unbiased estimators  and  of the population parameters will produce values that are _____ those produced by the biased estimators  and  .

Accepted Answer

A) smaller than 
B) larger than 
C) the same as 
D) sometimes larger than and sometimes smaller than

Question 11

The range is the descriptive statistic that indicates the

Accepted Answer

A) distance from the median. 
B) distance between the two most extreme scores. 
C) variability among means. 
D) distance between the mean and the extreme scores.

Question 12

Adding a constant to or subtracting a constant from each of the scores in a distribution

Accepted Answer

A) changes the value of the standard deviation by the amount of the constant. 
B) changes the value of the standard deviation by half the amount of the constant. 
C) changes the value of the standard deviation by 34% of the amount of the constant. 
D) does not change the value of the standard deviation.

Question 13

If we add  to   and subtract  from  ,the interval we have created

Accepted Answer

A) encompasses approximately 34% of the scores in the sample. 
B) encompasses approximately 68% of the scores in the sample. 
C) is approximately 68% of the range. 
D) is approximately 68% of the semi-interquartile range.

Question 14

The greater the variability in a set of scores,

Accepted Answer

A) the less accurately the scores are represented by the mean. 
B) the more accurately the scores are represented by the mean. 
C) the more similar and consistently close they are to the mean. 
D) the less similar and more consistently close they are to the mean.

Question 15

A psychology professor wanted to describe his/her class in terms of the personality characteristic of introversion/extroversion.The population variance was estimated to be 2.56.What does this mean?

Accepted Answer

A) When the professor uses the population mean to predict individuals' scores,he/she should expect to be in error by about 2.56. 
B) When the professor uses the population mean to predict individuals' scores,he/she should expect to be more accurate by about 2.56. 
C) It is impossible to tell because the mean is not known. 
D) The sample mean differs from the population mean by about 2.56.

Question 16

If the variance for a sample is computed and it is found to be rather large,the numbers

Accepted Answer

A) are tightly packed around the mode. 
B) are tightly packed around the mean. 
C) are spread out around the mean. 
D) in the sample are close to one another.

Question 17

The proper way to describe errors of prediction is to compute

Accepted Answer

A) the variance. 
B) the range. 
C) a z-score. 
D) a T-score.

Question 18

What is the range of the following data?

Accepted Answer

A) 3 
B) 5 
C) 6 
D) 9

Question 19

For the following data set,calculate the sample standard deviation. 1.72,4.01,2.55,0.67,1.93,2.05,2.69,3.13,1.22,3.84

Accepted Answer

A) 1.0243 
B) 1.0492 
C) 1.0797 
D) 1.1659

Question 20

If the sample standard deviation  for a set of data with N = 6 is found to be 3.17,then what is the sample variance  ?

Accepted Answer

A) 3.47 
B) 1.78 
C) 12.06 
D) 10.05

Exam 5: Measures of Variability: Range, variance, and Standard Deviation

The variance and standard deviation indicate how much the scores are spread out around

is the symbol for

For the following data set,calculate the sample variance. 1.72,4.01,2.55,0.67,1.93,2.05,2.69,3.13,1.22,3.84

What is the estimated population standard deviation of the following data?

What do , ,and have in common?