Question 1

Which of the following is not a measure of variability?

Accepted Answer

A)  Midrange 
B)  Standard deviation 
C)  Range 
D)  Interquartile range 
A)  Midrange 
B)  Standard deviation 
C)  Range 
D)  Interquartile range

Question 2

The descriptive measure of variability that is based on the concept of a variation about the mean is the

Accepted Answer

A)  range. 
B)  interquartile range. 
C)  absolute value of the range. 
D)  standard deviation. 
A)  range. 
B)  interquartile range. 
C)  absolute value of the range. 
D)  standard deviation.

Question 3

The coefficient of variation is the

Accepted Answer

A)  same as the variance. 
B)  standard deviation divided by the mean times 100. 
C)  square of the standard deviation. 
D)  mean divided by the standard deviation. 
A)  same as the variance. 
B)  standard deviation divided by the mean times 100. 
C)  square of the standard deviation. 
D)  mean divided by the standard deviation.

Question 4

When data are positively skewed, the mean will usually be

Accepted Answer

A)  greater than the median. 
B)  smaller than the median. 
C)  equal to the median. 
D)  positive. 
A)  greater than the median. 
B)  smaller than the median. 
C)  equal to the median. 
D)  positive.

Question 5

The variance can never be

Accepted Answer

A)  the same as the standard deviation. 
B)  larger than the standard deviation. 
C)  negative. 
D)  smaller than the standard deviation. 
A)  the same as the standard deviation. 
B)  larger than the standard deviation. 
C)  negative. 
D)  smaller than the standard deviation.

Question 6

Generally, which one of the following is the least appropriate measure of central tendency for a data set that contains outliers?

Accepted Answer

A)  Mean 
B)  Median 
C)  Mode 
D)  Midrange 
A)  Mean 
B)  Median 
C)  Mode 
D)  Midrange

Question 7

If a data set has an even number of observations, the median

Accepted Answer

A)  cannot be determined. 
B)  is the average value of the two middle items. 
C)  must be equal to the mean. 
D)  is the average value of the two middle items when all items are arranged in ascending order. 
A)  cannot be determined. 
B)  is the average value of the two middle items. 
C)  must be equal to the mean. 
D)  is the average value of the two middle items when all items are arranged in ascending order.

Question 8

The closing stock price of MNM Corporation for the last 7 trading days is shown below.   ​ The variance is

Accepted Answer

A)  2.828. 
B)  2.618. 
C)  8. 
D)  6.857. 
A)  2.828. 
B)  2.618. 
C)  8. 
D)  6.857.

Question 9

The geometric mean of 1, 1, 8 is

Accepted Answer

A)  10.0. 
B)  2.0. 
C)  3.33. 
D)  3.16. 
A)  10.0. 
B)  2.0. 
C)  3.33. 
D)  3.16.

Question 10

The measure of variability that is influenced most by extreme values is the

Accepted Answer

A)  variance. 
B)  standard deviation. 
C)  range. 
D)  interquartile range. 
A)  variance. 
B)  standard deviation. 
C)  range. 
D)  interquartile range.

Question 11

When n - 1 is used in the denominator to compute variance, the data set

Accepted Answer

A)  is a sample. 
B)  is a population. 
C)  could be either a sample or a population. 
D)  is from a census. 
A)  is a sample. 
B)  is a population. 
C)  could be either a sample or a population. 
D)  is from a census.

Question 12

The sum of deviations of the individual data elements from their mean is

Accepted Answer

A)  always greater than zero. 
B)  always less than zero. 
C)  sometimes greater than and sometimes less than zero, depending on the data elements. 
D)  always equal to zero. 
A)  always greater than zero. 
B)  always less than zero. 
C)  sometimes greater than and sometimes less than zero, depending on the data elements. 
D)  always equal to zero.

Question 13

If two groups of numbers have the same mean, then

Accepted Answer

A)  their standard deviations must also be equal. 
B)  their medians must also be equal. 
C)  their modes must also be equal. 
D)  other measures of location need not be the same. 
A)  their standard deviations must also be equal. 
B)  their medians must also be equal. 
C)  their modes must also be equal. 
D)  other measures of location need not be the same.

Question 14

The correlation coefficient ranges between

Accepted Answer

A)  0 and 1. 
B)  -1 and +1. 
C)  minus infinity and plus infinity. 
D)  1 and 100. 
A)  0 and 1. 
B)  -1 and +1. 
C)  minus infinity and plus infinity. 
D)  1 and 100.

Question 15

Since the median is the middle value of a data set it

Accepted Answer

A)  must always be smaller than the mode. 
B)  must always be larger than the mode. 
C)  must always be smaller than the mean. 
D)  none of these alternatives is correct. 
A)  must always be smaller than the mode. 
B)  must always be larger than the mode. 
C)  must always be smaller than the mean. 
D)  none of these alternatives is correct.

Question 16

Geometric mean is a measure of

Accepted Answer

A)  location. 
B)  dispersion. 
C)  variability. 
D)  weight. 
A)  location. 
B)  dispersion. 
C)  variability. 
D)  weight.

Question 17

The sample variance

Accepted Answer

A)  is always smaller than the true value of the population variance. 
B)  is always larger than the true value of the population variance. 
C)  could be smaller, equal to, or larger than the true value of the population variance. 
D)  can never be zero. 
A)  is always smaller than the true value of the population variance. 
B)  is always larger than the true value of the population variance. 
C)  could be smaller, equal to, or larger than the true value of the population variance. 
D)  can never be zero.

Question 18

The variance of a sample of 100 observations equals 64. The standard deviation of the sample equals

Accepted Answer

A)  8. 
B)  10. 
C)  4096. 
D)  10,000. 
A)  8. 
B)  10. 
C)  4096. 
D)  10,000.

Question 19

In computing the mean of a sample, the value of ∑xi is divided by

Accepted Answer

A)  n. 
B)  n - 1. 
C)  n + 1. 
D)  n - 2. 
A)  n. 
B)  n - 1. 
C)  n + 1. 
D)  n - 2.

Question 20

Which of the following symbols represents the standard deviation of the population?

Accepted Answer

A)  σ2 
B)  σ 
C)  μ 
D)    
A)  σ2 
B)  σ 
C)  μ 
D)

Exam 3: Descriptive Statistics: Numerical Measures

Which of the following is not a measure of variability?

The descriptive measure of variability that is based on the concept of a variation about the mean is the

The coefficient of variation is the

When data are positively skewed, the mean will usually be

The variance can never be

Generally, which one of the following is the least appropriate measure of central tendency for a data set that contains outliers?

If a data set has an even number of observations, the median

The closing stock price of MNM Corporation for the last 7 trading days is shown below. ​ The variance is

The geometric mean of 1, 1, 8 is

The measure of variability that is influenced most by extreme values is the

When n - 1 is used in the denominator to compute variance, the data set

The sum of deviations of the individual data elements from their mean is

If two groups of numbers have the same mean, then

The correlation coefficient ranges between

Since the median is the middle value of a data set it

Geometric mean is a measure of

The sample variance

The variance of a sample of 100 observations equals 64. The standard deviation of the sample equals

In computing the mean of a sample, the value of ∑xi is divided by

Which of the following symbols represents the standard deviation of the population?

Data and Statistics

Descriptive Statistics: Tabular and Graphical Displays

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Hypothesis Tests

Inference About Means and Proportions With Two Populations

Inferences About Population Variances

Comparing Multiple Proportions, Tests of Independence and Goodness of Fit

Experimental Design and Analysis of Variance

Simple Linear Regression

Multiple Regression

Regression Analysis: Model Building

Time Series Analysis and Forecasting

Nonparametric Methods

Decision Analysis

Index Numbers

Statistical Methods for Quality Control

Sample Survey

Filters

The closing stock price of MNM Corporation for the last 7 trading days is shown below. The variance is

In computing the mean of a sample, the value of ∑x_i is divided by