Question 1

The most frequently used measure of central tendency is:

Accepted Answer

A)  median. 
B)  mean. 
C)  mode. 
D)  middle value.

Question 2

Explain how Tchebysheff's theorem can be used to help describe data in a population or a sample.

Accepted Answer

The answer of Explain how Tchebysheff's theorem can be used...

Question 3

The credit card balances for customers at State Bank and Trust has a mean equal to $800 and a standard deviation equal to $60.00. Kevin Smith's balance is $1,352. Based on this, his standardized value is 9.20.

Accepted Answer

A) True 
 B)False

Question 4

If a distribution for a quantitative variable is thought to be nearly symmetric with very little variation, and a box and whisker plot is created for this distribution, which of the following is true?

Accepted Answer

A)  The box will be quite wide but the whisker will be very short. 
B)  The left and right-hand edges of the box will be approximately equal distance from the median. 
C)  The whiskers should be about half as long as the box is wide. 
D)  The upper whisker will be much longer than the lower whisker.

Question 5

A large retail company gives an employment screening test to all prospective employees. Franklin Gilman recently took the test and it was reported back to him that his score placed him at the 80th percentile. Therefore:

Accepted Answer

A)  80 people who took the test scored below Franklin. 
B)  Franklin scored as high or higher than 80 percent of the people who took the test. 
C)  Franklin was in the bottom 20 percent of those that have taken the test. 
D)  Franklin's score has a z-score of 80.

Question 6

Incomes in a particular market area are known to be right-skewed with a mean equal to $33,100. In a report issued recently, a manager stated that at least 89 percent of all incomes are in the range of $26,700 to $39,500, and this was based on Tchebysheff's theorem. Given these facts, what is the standard deviation for the incomes in this market area?

Accepted Answer

A)  Approximately $6,400 
B)  Approximately $3,200 
C)  Approximately $2,133 
D)  Approximately $4266

Question 7

In order to compute the mean and standard deviation, the level of data measurement should be:

Accepted Answer

A)  ratio or interval. 
B)  qualitative. 
C)  nominal. 
D)  ordinal.

Question 8

First Pacific Bank has determined that the mean checking account balance for all its customers is currently $743.50. Based on this, it is fair to say that about half the customers have balances exceeding $743.50.

Accepted Answer

A) True 
 B)False

Question 9

The box and whisker plot CANNOT be used to identify:

Accepted Answer

A)  skewedness. 
B)  centerness. 
C)  outliers. 
D)  symmetry.

Question 10

Based on the empirical rule we can assume that all bell-shaped distributions have approximately 95 percent of the values within ± 2 standard deviations of the mean.

Accepted Answer

A) True 
 B)False

Question 11

At a sawmill in Oregon, a process improvement team measured the diameters for a sample of 1,500 logs. The following summary statistics were computed:  Given this information, for a box and whisker plot which of the following statements is appropriate?

Accepted Answer

A)  Seventy-five percent of the trees in the sample have values between 8.9 in. and 15.6 in. 
B)  Virtually all of the data should fall between 0 in. and 25.65 in. 
C)  No tree will have a diameter of more than 22.3 in. 
D)  Fifty percent of the trees will have diameters between 13.5 in. and 15.6 in.

Question 12

For a given set of data, if the data are treated as a population, the calculated standard deviation will be less than it would be had the data been treated as a sample.

Accepted Answer

A) True 
 B)False

Question 13

A small company has 7 employees. The numbers of years these employees have worked for this company are shown as follows:  Based upon this information, the mean number of years that employees have been with this company is:

Accepted Answer

A)  16 
B)  x 
C)  8.40 
D)  10

Question 14

A population measure, such as the population mean, is called a:

Accepted Answer

A)  statistic. 
B)  parameter. 
C)  prime number. 
D)  sample value.

Question 15

You are given the following data:  Assuming that the data reflect the population of interest, the mean of the population is 36.00.

Accepted Answer

A) True 
 B)False

Question 16

The sample mean is an estimate of μ and may be either higher or lower than μ depending on the sample.

Accepted Answer

A) True 
 B)False

Question 17

A lakeside neighborhood in Washington is home to a couple of successful baseball and football players in Seattle. If news articles usually report the median household income in that neighborhood rather than the mean income, this would be because income is a left-skewed distribution.

Accepted Answer

A) True 
 B)False

Question 18

The following data reflect the number of customers who return merchandise for a refund on Monday. Note these data reflect the population of all 10 Mondays for which data are available.  Assume that this same exact pattern of data were replicated for the next ten days. How would this affect the standard deviation for the new population with 20 items?

Accepted Answer

A)  The standard deviation would be doubled. 
B)  The standard deviation would be cut in half. 
C)  The standard deviation would not be changed. 
D)  There is no way of knowing the exact impact without knowing how the mean is changed.

Question 19

A store manager tracks the number of customer complaints each week. The following data reflect a random sample of ten weeks.  The standard deviation for these data is approximately 27.78.

Accepted Answer

A) True 
 B)False

Question 20

Dynamic random-access memory (DRAM) memory chips are made from silicon wafers in manufacturing facilities through a very complex process called wafer fabs. The wafers are routed through the fab machines in an order that is referred to as a recipe. The wafers may go through the same machine several times as the chip is created. The data file DRAM Chips contains a sample of processing times, measured in fractions of hours, at a particular machine center for one chip recipe. Calculate the 80th percentile for processing time.

Accepted Answer

A)  0.40 minutes 
B)  0.35 minutes 
C)  0.45 minutes 
D)  0.20 minutes

Exam 3: Describing Data Using Numerical Measures

The most frequently used measure of central tendency is:

Explain how Tchebysheff's theorem can be used to help describe data in a population or a sample.

The credit card balances for customers at State Bank and Trust has a mean equal to $800 and a standard deviation equal to $60.00. Kevin Smith's balance is $1,352. Based on this, his standardized value is 9.20.

If a distribution for a quantitative variable is thought to be nearly symmetric with very little variation, and a box and whisker plot is created for this distribution, which of the following is true?

A large retail company gives an employment screening test to all prospective employees. Franklin Gilman recently took the test and it was reported back to him that his score placed him at the 80th percentile. Therefore:

In order to compute the mean and standard deviation, the level of data measurement should be:

First Pacific Bank has determined that the mean checking account balance for all its customers is currently $743.50. Based on this, it is fair to say that about half the customers have balances exceeding $743.50.

The box and whisker plot CANNOT be used to identify:

Based on the empirical rule we can assume that all bell-shaped distributions have approximately 95 percent of the values within ± 2 standard deviations of the mean.

At a sawmill in Oregon, a process improvement team measured the diameters for a sample of 1,500 logs. The following summary statistics were computed: Given this information, for a box and whisker plot which of the following statements is appropriate?

For a given set of data, if the data are treated as a population, the calculated standard deviation will be less than it would be had the data been treated as a sample.

A small company has 7 employees. The numbers of years these employees have worked for this company are shown as follows: Based upon this information, the mean number of years that employees have been with this company is:

A population measure, such as the population mean, is called a:

You are given the following data: Assuming that the data reflect the population of interest, the mean of the population is 36.00.

The sample mean is an estimate of μ and may be either higher or lower than μ depending on the sample.

A lakeside neighborhood in Washington is home to a couple of successful baseball and football players in Seattle. If news articles usually report the median household income in that neighborhood rather than the mean income, this would be because income is a left-skewed distribution.

A store manager tracks the number of customer complaints each week. The following data reflect a random sample of ten weeks. The standard deviation for these data is approximately 27.78.