Question 1

Measures of variability describe typical values in the data.

Accepted Answer

A) True 
 B)False

Question 2

According to Tchebysheff's Theorem, at least 96% of observations should fall within 5 standard deviations of the mean.

Accepted Answer

A) True 
 B)False

Question 3

A random sample from an unknown population had a sample standard deviation of zero. Which one of the following is a reasonable conclusion?

Accepted Answer

A)  The sample range must be zero. 
B)  An error was made in computing the sample standard deviation. It must always be greater than zero. 
C)  The population standard deviation must be zero. 
D)  The population standard deviation must be zero when the mean is zero. 
E)  None of these. 
A)  The sample range must be zero. 
B)  An error was made in computing the sample standard deviation. It must always be greater than zero. 
C)  The population standard deviation must be zero. 
D)  The population standard deviation must be zero when the mean is zero. 
E)  None of these.

Question 4

Which of the following statements is true?

Accepted Answer

A)  The sum of the deviations from the mean is always zero. 
B)  The sum of the squared deviations from the mean is always zero. 
C)  The standard deviation is always smaller than the variance. 
D)  The distance between the first and third quartiles is twice the distance between the first and second quartiles. 
E)  None of these is true. 
A)  The sum of the deviations from the mean is always zero. 
B)  The sum of the squared deviations from the mean is always zero. 
C)  The standard deviation is always smaller than the variance. 
D)  The distance between the first and third quartiles is twice the distance between the first and second quartiles. 
E)  None of these is true.

Question 5

While Tchebysheff's Theorem applies to any distribution, regardless of shape, the empirical rule applies only to distributions that are mound-shaped.

Accepted Answer

A) True 
 B)False

Question 6

In a mound-shaped distribution, there is no difference in the values of the mean, and median.

Accepted Answer

A) True 
 B)False

Question 7

The larger the values of the sample variance   and sample standard deviation s, the greater the variability in the data.

Accepted Answer

A) True 
 B)False

Question 8

The range is considered the weakest measure of variability.

Accepted Answer

A) True 
 B)False

Question 9

If the variability of a set of data is very small, then the sample variance may be negative.

Accepted Answer

A) True 
 B)False

Question 10

The median is a measure of center that divides an ordered array of data into two halves; if the data are arranged in ascending order from smallest to largest, all the observations below the median are smaller than or equal to it, while all the observations above the median are equal to it or larger.

Accepted Answer

A) True 
 B)False

Question 11

If the distribution of sales is thought to be symmetric with very little variation, then:

Accepted Answer

A)  the whiskers on a box and whisker plot should be about half as long as the box is wide 
B)  the width of the box in a box and whisker plot will be very wide but the whisker will be very short 
C)  the left and right edges of the box in a box and whisker plot will be approximately equal distance from the second quartile 
D)  none of these 
E)  all of these 
A)  the whiskers on a box and whisker plot should be about half as long as the box is wide 
B)  the width of the box in a box and whisker plot will be very wide but the whisker will be very short 
C)  the left and right edges of the box in a box and whisker plot will be approximately equal distance from the second quartile 
D)  none of these 
E)  all of these

Question 12

When all the numbers in the data set are the same, the standard deviations must be zero.

Accepted Answer

A) True 
 B)False

Question 13

Tchebysheff's Theorem gives a lower bound to the fraction of measurements to be found in an interval constructed as   .

Accepted Answer

A) True 
 B)False

Question 14

A graphical device that highlights the highest and lowest values in a data set, along with a number of other key observations in an ordered array of the data, such as the upper quartile, the middle value (or median), and the lower quartile, is called:

Accepted Answer

A)  a boxplot 
B)  a five-number summary 
C)  a dotplot 
D)  a stem-and-leaf plot 
E)  a histogram 
A)  a boxplot 
B)  a five-number summary 
C)  a dotplot 
D)  a stem-and-leaf plot 
E)  a histogram

Question 15

In assembling a home appliance, workers generally finish the process within 30 minutes to one hour. Occasionally, due to system failures, the assembly process takes a long time, possibly as long as 4 to 5 hours. What is the most appropriate measure of central tendency to use in this case if you want the measure to be representative of most of the observed times?
______________
Why is it the most appropriate measure?
________________________________________________________

Accepted Answer

Median; Median is th

Question 16

Assume that all employees of a community college received a $150 monthly raise.
a. How would this affect the mean of salaries?
____________________________
b. How would this affect the standard deviation of salaries?
__________________________________________

Accepted Answer

The mean will increa

Question 17

Jessica has been keeping track of what she spends to eat out. The last week's expenditures for meals eaten out were $15.69, $15.95, $16.19, $20.91, $17.49, $24.53, and $17.66. The mean amount Jessica spends on meals is $18.35.

Accepted Answer

A) True 
 B)False

Question 18

The following data represent scores on a 15 point aptitude test: 8, 10, 15, 12, 14, and 13.
a. Complete the sample mean for the original data.
______________
Subtract 5 from every observation and complete the sample mean for the new data.
______________
b. Complete the sample variance for the original data.
______________
Subtract 5 from every observation and complete the sample variance for the new data.
______________
c. What effect, if any, does subtracting 5 from every observation have on the sample mean and sample variance?
________________________________________________________

Accepted Answer

12; 7; 6.8; 6.8; The sample me

Question 19

Which one of the values below represents the upper quartile of the data set 10, 12, 16, 7, 9, 7, 41, and 14?

Accepted Answer

A)  8 
B)  15.5 
C)  7 
D)  24 
E)  10 
A)  8 
B)  15.5 
C)  7 
D)  24 
E)  10

Question 20

The times required to service customers' cars at a repair shop are skewed to the right with a mean of 2.5 hours and a standard deviation of 0.75 hours. What can be said about the proportion of cars whose service time is either less than one hour or more than four hours?

Accepted Answer

Applying the Tchebysheff 's Th

Measures of variability describe typical values in the data.

According to Tchebysheff's Theorem, at least 96% of observations should fall within 5 standard deviations of the mean.

A random sample from an unknown population had a sample standard deviation of zero. Which one of the following is a reasonable conclusion?

Which of the following statements is true?

While Tchebysheff's Theorem applies to any distribution, regardless of shape, the empirical rule applies only to distributions that are mound-shaped.

In a mound-shaped distribution, there is no difference in the values of the mean, and median.

The larger the values of the sample variance and sample standard deviation s, the greater the variability in the data.

The range is considered the weakest measure of variability.

If the variability of a set of data is very small, then the sample variance may be negative.

The median is a measure of center that divides an ordered array of data into two halves; if the data are arranged in ascending order from smallest to largest, all the observations below the median are smaller than or equal to it, while all the observations above the median are equal to it or larger.

If the distribution of sales is thought to be symmetric with very little variation, then:

When all the numbers in the data set are the same, the standard deviations must be zero.

Tchebysheff's Theorem gives a lower bound to the fraction of measurements to be found in an interval constructed as $Tchebysheff's Theorem gives a lower bound to the fraction of measurements to be found in an interval constructed as .$ .

A graphical device that highlights the highest and lowest values in a data set, along with a number of other key observations in an ordered array of the data, such as the upper quartile, the middle value (or median), and the lower quartile, is called:

Assume that all employees of a community college received a $150 monthly raise. a. How would this affect the mean of salaries? b. How would this affect the standard deviation of salaries? ______________

Jessica has been keeping track of what she spends to eat out. The last week's expenditures for meals eaten out were $15.69, $15.95, $16.19, $20.91, $17.49, $24.53, and $17.66. The mean amount Jessica spends on meals is $18.35.

Which one of the values below represents the upper quartile of the data set 10, 12, 16, 7, 9, 7, 41, and 14?

The times required to service customers' cars at a repair shop are skewed to the right with a mean of 2.5 hours and a standard deviation of 0.75 hours. What can be said about the proportion of cars whose service time is either less than one hour or more than four hours?

Describing Data With Graphs

Describing Bivariate Data

Probability and Probability Distributions

Several Useful Discrete Distributions

The Normal Probability Distribution

Sampling Distributions

Large-Sample Estimation

Large-Sample Tests of Hypotheses

Inference From Small Samples

The Analysis of Variance

Linear Regression and Correlation

Multiple Regression Analysis

Analysis of Categorical Data

Nonparametric Statistics

Filters

Exam 2: Describing Data With Numerical Measures

Measures of variability describe typical values in the data.

According to Tchebysheff's Theorem, at least 96% of observations should fall within 5 standard deviations of the mean.

A random sample from an unknown population had a sample standard deviation of zero. Which one of the following is a reasonable conclusion?

Which of the following statements is true?

While Tchebysheff's Theorem applies to any distribution, regardless of shape, the empirical rule applies only to distributions that are mound-shaped.

In a mound-shaped distribution, there is no difference in the values of the mean, and median.

The larger the values of the sample variance and sample standard deviation s, the greater the variability in the data.

The range is considered the weakest measure of variability.

If the variability of a set of data is very small, then the sample variance may be negative.

If the distribution of sales is thought to be symmetric with very little variation, then:

When all the numbers in the data set are the same, the standard deviations must be zero.

Tchebysheff's Theorem gives a lower bound to the fraction of measurements to be found in an interval constructed as .

A graphical device that highlights the highest and lowest values in a data set, along with a number of other key observations in an ordered array of the data, such as the upper quartile, the middle value (or median), and the lower quartile, is called:

Assume that all employees of a community college received a $150 monthly raise. a. How would this affect the mean of salaries? ____________________________ b. How would this affect the standard deviation of salaries? __________________________________________

Jessica has been keeping track of what she spends to eat out. The last week's expenditures for meals eaten out were $15.69, $15.95, $16.19, $20.91, $17.49, $24.53, and $17.66. The mean amount Jessica spends on meals is $18.35.

Which one of the values below represents the upper quartile of the data set 10, 12, 16, 7, 9, 7, 41, and 14?

The times required to service customers' cars at a repair shop are skewed to the right with a mean of 2.5 hours and a standard deviation of 0.75 hours. What can be said about the proportion of cars whose service time is either less than one hour or more than four hours?

Describing Data With Graphs

Describing Bivariate Data

Probability and Probability Distributions

Several Useful Discrete Distributions

The Normal Probability Distribution

Sampling Distributions

Large-Sample Estimation

Large-Sample Tests of Hypotheses

Inference From Small Samples

The Analysis of Variance

Linear Regression and Correlation

Multiple Regression Analysis

Analysis of Categorical Data

Nonparametric Statistics

Filters

Tchebysheff's Theorem gives a lower bound to the fraction of measurements to be found in an interval constructed as $Tchebysheff's Theorem gives a lower bound to the fraction of measurements to be found in an interval constructed as .$ .

Assume that all employees of a community college received a $150 monthly raise. a. How would this affect the mean of salaries? b. How would this affect the standard deviation of salaries? ______________