Deck 3: Descriptive Statistics

Question 1

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

Answer 1

True

Question 2

The coefficient of variation is unitless.

Answer 2

True

Question 3

Average deviation is a common measure of the variability of data containing a set of numbers.

Answer 3

False

Question 4

The lowest appropriate level of measurement for the median is ordinal.

Question 5

Skewness and kurtosis of a data set are measures of the shape of the distribution.

Question 6

Statistical measures used to yield information about the center or the middle parts of a group of numbers are called the measures of central tendency.

Question 7

Kurtosis is a measure of the association between two numerical variables.

Question 8

For grouped data,the midpoint of each class interval is used to represent all the values in a class interval.

Question 9

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

Question 10

The average of the squared deviations about the arithmetic mean is called the variance.

Question 11

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

Question 12

For grouped data,the mode is the class midpoint of the modal class where the model class is the class interval with the greatest frequency.

Question 13

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

Question 14

If the mean of a distribution is greater than the median,then the distribution is positively skewed.

Question 15

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

Question 16

The median for ungrouped raw data is more complicated to compute then the median for grouped data.

Question 17

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

Question 18

The most appropriate measure of central tendency for nominal-level data is the median.

Question 19

An appropriate measure of central tendency for ordinal data is the mode.

Question 20

The middle value in an ordered array of numbers is called the mode.

Question 21

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 44,39,41,35,and 41.What is the mean absolute deviation for this sample data?

A)0
B)12
C)3
D)2.4
E)1.2

Question 22

A sample was taken of the salaries of four employees from a large company.The following are their salaries (in thousands of dollars)for this year: 33,36,41,and 47.The median of their salaries is approximately

A)38.5
B)34.5
C)34
D)44.5
E)38

Question 23

According to Chebyshev's Theorem,approximately how many values in a large data set will be within 2 standard deviations of the mean?

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

Question 24

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?

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

Question 25

The empirical rule says that approximately what percentage of the values would be within 1 standard deviation of the mean in a bell shaped set of data?

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

Question 26

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

Question 27

A box and whisker plot is determined from the mean,the smallest and the largest values,and the lower and upper quartile.

Question 28

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?

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

Question 29

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

A)78
B)80
C)86
D)84
E)88

Question 30

A sample was taken of the salaries of four employees from a large company.The following are their salaries (in thousands of dollars)for this year: 33,36,41,and 47.The variance of their salaries is approximately

A)28.19
B)75.59
C)37.58
D)6.13
E)5.31

Question 31

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 median time (in minutes)required for this trip was _______.

A)39
B)41
C)37.5
D)38
E)35.5

Question 32

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 variance for this sample data?

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

Question 33

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

A)79
B)82
C)86
D)92
E)76

Question 34

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

Question 35

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

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

Question 36

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

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

Question 37

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 _______.

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 38

If the median of a distribution is greater than mean,then the distribution is skewed to the left.

Question 39

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 mode time required for this trip was _______.

A)39
B)41
C)37.5
D)38
E)35

Question 40

The number of standard deviations that a value (x)is above or below the mean is the _________________.

A)absolute deviation
B)coefficient of variation
C)interquartile range
D)z score
E)correlation coefficient

Question 41

The average starting salary for graduates at a university is $33,000 with a standard deviation of $2,000.If a histogram of the data shows that it takes on a mound shape,the empirical rule says that approximately 68% of the graduates would have a starting salary between _______.

A)29,000 and 37,000
B)27,000 and 39,000
C)25,000 and 41,000
D)29,000 and 37,000
E)21,000 and 29,000

Question 42

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 _______.

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

Question 43

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.Approximately 95% of the batteries will last between ________________.

A)70 and 80 months
B)60 and 90 months
C)65 and 85 months
D)55 and 95 months
E)60 and 100 months

Question 44

David Desreumaux,VP of Human Resources of American First Banks (AFB),is reviewing the employee training programs of AFB banks.His staff reports several statistics for teller training hours.The mean is 20 hours,the standard deviation is 5 hours,the median is 15 hours,and mode is 10 hours.The Pearsonian coefficient of skewness for teller training hours is __________.

A)6
B)1
C)3
D)4
E)0

Question 45

The following frequency distribution was constructed for the wait times to check out at the grocery store. The frequency distribution reveals that the wait times to check out at the grocery store are _______.

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

Question 46

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

Question 47

The average starting salary for graduates at a university is $33,000 with a standard deviation of $2,000.If a histogram of the data shows that it takes on a mound shape,the empirical rule says that approximately 95% of the graduates would have a starting salary between _______.

A)29,000 and 37,000
B)27,000 and 39,000
C)25,000 and 41,000
D)29,000 and 37,000
E)21,000 and 29,000

Question 48

The mean life of a particular brand of light bulb is 1200 hours and the standard deviation is 50 hours.It can be concluded that at least 89% of this brand of bulbs will last between _______.

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 49

Liz Chapa manages a portfolio of 250 common stocks.Her staff compiled the following performance statistics for two new stocks. The coefficient of variation for Salas Products,Inc.is __________.

A)300%
B)100%
C)33%
D)5%
E)23%

Question 50

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)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 51

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

Question 52

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?

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

Question 53

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.Approximately 99.7% of the batteries will last between ________________.

A)70 and 80 months
B)60 and 90 months
C)65 and 85 months
D)55 and 95 months
E)50 and 100 months

Question 54

Karen Merlott,VP for Strategic Planning at a recruitment firm,recently conducts a survey to determine customer satisfaction with job placement.She distributed the survey to 45 of the most recently placed executives.Two items on a survey questionnaire them to rate the importance of "initial interview process" and "satisfaction of final job placement" on a scale of 1 to 10 (with 1 meaning "not important" and 10 meaning "highly important").Her staff assembled the following statistics on these two items. What can Karen conclude from these statistics?

A)The Initial Interview Process distribution is positively skewed.
B)The Initial Interview Process distribution is not skewed.
C)The Satisfaction of Final Job Placement distribution is negatively skewed.
D)The Satisfaction of Final Job Placement distribution is positively skewed.
E)Both are symmetrically distributed.

Question 55

The mean life of a particular brand of light bulb is 1200 hours and the standard deviation is 75 hours.Tests show that the life of the bulb is approximately normally distributed.It can be concluded that approximately 68% of the bulbs will last between _______.

A)900 and 1100 hours
B)950 and 1050 hours
C)975 and 1475 hours
D)1050 and 1350 hours
E)1125 and 1275 hours

Question 56

David Desreumaux,VP of Human Resources of American First Banks (AFB),is reviewing the employee training programs of AFB banks.His staff compiled the following table of regional statistics on teller training hours. What can David conclude from these statistics?

A)The Southeast distribution is symmetrical.
B)The Southwest distribution is skewed to the left.
C)The Southeast distribution has the greater dispersion.
D)The Southeast distribution is skewed to the left.
E)The two distributions are symmetrical.

Question 57

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.Approximately 68% of the batteries will last between ________________.

A)70 and 80 months
B)60 and 90 months
C)65 and 85 months
D)55 and 95 months
E)60 and 100 months

Question 58

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 ____________.

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 59

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?

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.