Question 1

A statistics student made the following grades on 7 tests: 76,82,92,95,79,86,and 92.What is the median grade?

Accepted Answer

A)  86
B)  76
C)  82
D)  94
E)  95 A

Question 2

The most frequently occurring value in a set of data is called the mode.

Accepted Answer

A) True 
 B)False  True

Question 3

Jessica Salas,president of Salas Products,is reviewing the warranty policy for her company's new model of automobile batteries.Life tests performed on a sample of 100 batteries indicated: (1)an average life of 75 months,(2)a standard deviation of 5 months,and (3)a bell shaped battery life distribution.What percentage of the batteries will fail within the first 65 months of use?

Accepted Answer

A)  0.5%
B)  1%
C)  2.5%
D)  5%
E)  7.5% C

Question 4

It is inappropriate to use the mean to analyze data that are not at least interval level in measurement.

Accepted Answer

A) True 
 B)False

Question 5

Computations of the variance and standard deviation using grouped data are potentially only
approximation of the actual variance and standard deviation.

Accepted Answer

A) True 
 B)False

Question 6

According to Chebyshev's Theorem how many values in a data set will be within 3 standard deviations of the mean?

Accepted Answer

A)  At least 75%
B)  At least 68%
C)  At least 95%
D)  At least 89%
E)  At least 99%

Question 7

The empirical rule says that approximately what percentage of the values would be within 2 standard deviations of the mean in a bell shaped set of data?

Accepted Answer

A)  95%
B)  68%
C)  50%
D)  97.7%
E)  100%

Question 8

The sample standard deviation is calculated by taking the square root of the population standard deviation.

Accepted Answer

A) True 
 B)False

Question 9

The following box and whisker plot was constructed for the age of accounts receivable.  The box and whisker plot reveals that the accounts receivable ages are _______.

Accepted Answer

A)  skewed to the left
B)  skewed to the right
C)  not skewed
D)  normally distributed
E)  symmetrical

Question 10

A sample of 117 records of the selling price in dollars of homes from Feb 15 to Apr 30,2013 was taken from the files maintained by the Albuquerque Board of Realtors.The following are
Summary statistics for the selling prices.
 From this we can conclude that,

Accepted Answer

A)  There are no outliers
B)  More homes were sold for greater than $121750 than for less than $77650
C)  68% of the selling price of homes is from $77650 to $121750
D)  25% of the selling price of homes is at least $121750
E)  The distribution of selling price of homes is negatively skewed.

Question 11

A commuter travels many miles to work each morning.She has timed this trip 5 times during the last month.The time (in minutes)required to make this trip was 34,39,41,35,and 41.The mean time (in minutes)required for this trip was _______.

Accepted Answer

A)  35
B)  41
C)  37.5
D)  38
E)  35.5

Question 12

A commuter travels many miles to work each morning.She has timed this trip 5 times during the last month.The time (in minutes)required to make this trip was 38,33,36,47,and 41.What is the standard deviation for this sample data?

Accepted Answer

A)  28.5
B)  11
C)  22.8
D)  5.34
E)  4.77

Question 13

The sum of deviations about the arithmetic mean is always equal to zero.

Accepted Answer

A) True 
 B)False

Question 14

Shaun Connor,Human Resources Manager forAmerican Oil Terminals (AOT),is reviewing the operator training hours at AOT nationally.His staff compiled the following table of national statistics on operators training hours.  What can Shaun conclude from these statistics?

Accepted Answer

A)  The East Coast distribution is skewed to the left.
B)  The East Coast distribution is skewed to the right.
C)  The West Coast distribution is skewed to the left.
D)  The West Coast distribution is skewed to the right.
E)  Both distributions are symmetrical.

Question 15

An outlier of a data set is determined from the lower and upper quartile

Accepted Answer

A) True 
 B)False

Question 16

The mean life of a particular brand of light bulb is 1200 hours and the standard deviation is 50 hours.We can conclude that at least 75% of this brand of bulbs will last between _______.

Accepted Answer

A)  1100 and 1300 hours
B)  1150 and 1250 hours
C)  1050 and 1350 hours
D)  1000 and 1400 hours
E)  950 and 1450 hours

Question 17

The following box and whisker plot was constructed for the age of accounts receivable.  The box and whisker plot reveals that the accounts receivable ages are _______.

Accepted Answer

A)  skewed to the left
B)  skewed to the right
C)  not skewed
D)  normally distributed
E)  symmetrical

Question 18

A nonzero value of the skewness indicates asymmetry of the distribution of the data.

Accepted Answer

A) True 
 B)False

Question 19

In its Industry Norms and Key Business Ratios,Dun & Bradstreet reported that Q1,Q2,and Q3 for 2,037 gasoline service stations' sales to inventory ratios were 20.8,33.4,and 53.8,respectively.From this we can conclude that ____________.

Accepted Answer

A)  68% of these service stations had sales to inventory ratios of 20.8 or less
B)  50% of these service stations had sales to inventory ratios of 33.4 or less
C)  50% of these service stations had sales to inventory ratios of 53.8 or more
D)  95% of these service stations had sales to inventory ratios of 33.4 or more
E)  99% of these service stations had sales to inventory ratios of 53.8 or more

Question 20

The following frequency distribution was constructed for the wait times in the emergency room.  The frequency distribution reveals that the wait times in the emergency room are _______.

Accepted Answer

A)  skewed to the left
B)  skewed to the right
C)  not skewed
D)  normally distributed
E)  symmetrical

Exam 3: Descriptive Statistics

A statistics student made the following grades on 7 tests: 76,82,92,95,79,86,and 92.What is the median grade?

The most frequently occurring value in a set of data is called the mode.

It is inappropriate to use the mean to analyze data that are not at least interval level in measurement.

Computations of the variance and standard deviation using grouped data are potentially only approximation of the actual variance and standard deviation.

According to Chebyshev's Theorem how many values in a data set will be within 3 standard deviations of the mean?

The empirical rule says that approximately what percentage of the values would be within 2 standard deviations of the mean in a bell shaped set of data?

The sample standard deviation is calculated by taking the square root of the population standard deviation.

The following box and whisker plot was constructed for the age of accounts receivable. The box and whisker plot reveals that the accounts receivable ages are _______.

A sample of 117 records of the selling price in dollars of homes from Feb 15 to Apr 30,2013 was taken from the files maintained by the Albuquerque Board of Realtors.The following are Summary statistics for the selling prices. From this we can conclude that,

A commuter travels many miles to work each morning.She has timed this trip 5 times during the last month.The time (in minutes) required to make this trip was 34,39,41,35,and 41.The mean time (in minutes) required for this trip was _______.

A commuter travels many miles to work each morning.She has timed this trip 5 times during the last month.The time (in minutes) required to make this trip was 38,33,36,47,and 41.What is the standard deviation for this sample data?

The sum of deviations about the arithmetic mean is always equal to zero.

Shaun Connor,Human Resources Manager forAmerican Oil Terminals (AOT) ,is reviewing the operator training hours at AOT nationally.His staff compiled the following table of national statistics on operators training hours. What can Shaun conclude from these statistics?

An outlier of a data set is determined from the lower and upper quartile

The mean life of a particular brand of light bulb is 1200 hours and the standard deviation is 50 hours.We can conclude that at least 75% of this brand of bulbs will last between _______.

The following box and whisker plot was constructed for the age of accounts receivable. The box and whisker plot reveals that the accounts receivable ages are _______.

A nonzero value of the skewness indicates asymmetry of the distribution of the data.

In its Industry Norms and Key Business Ratios,Dun & Bradstreet reported that Q1,Q2,and Q3 for 2,037 gasoline service stations' sales to inventory ratios were 20.8,33.4,and 53.8,respectively.From this we can conclude that ____________.

The following frequency distribution was constructed for the wait times in the emergency room. The frequency distribution reveals that the wait times in the emergency room are _______.