Question 1

The following data reflect the number of customers who test drove new cars each day for a sample of 20 days at the Redfield Ford Dealership.  Given these data, what is the range?
A) 14
B) 1
C) Approximately 3.08
D) 5.95

Accepted Answer

The answer of The following data reflect the number of...

Question 2

If a data set has 740 values that have been sorted from low to high, which value in the data set will be the 20th percentile?
A) The average of the 148th and 149th values
B) The 20th value
C) The 148th value
D) None of the above

Accepted Answer

The 20th percentile is the value below which 20% of the data falls. In this case, 20% of 740 is 148. Therefore, the 20th percentile is the average of the 148th and 149th values.

Question 3

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.  Based on these data, what is the standard deviation?
A) 13.03
B) 12.36
C) 39
D) 152.8

Accepted Answer

The answer of The following data reflect the number of...

Question 4

Which of the following measures is not affected by extreme values in the data?
A) The mean
B) The median
C) The range
D) The standard deviation

Accepted Answer

The median is not affected by extreme values because it is the middle value in a data set when the numbers are arranged in order, making it resistant to outliers.

Question 5

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) 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.

Accepted Answer

Given the distribution is nearly symmetric with very little variation, the distances from the median to the left and right edges of the box (which represent the first and third quartiles, respectively) would be approximately equal. This symmetry around the median is characteristic of a symmetric distribution.

Question 6

If a data set has 1,133 sorted values, what value corresponds to the 3rd quartile?
A) The 250th value
B) The 850th value
C) The 760th value
D) The 849th value

Accepted Answer

The 3rd quartile (Q3) corresponds to the 75th percentile of a data set. To find the position of Q3 in a sorted list of 1,133 values, multiply 1,133 by 0.75, which gives 849.75. Since we cannot have a fraction of a position, we round up to the nearest whole number, which is the 850th value.

Question 7

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?
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.

Accepted Answer

The answer of At a sawmill in Oregon, a process...

Question 8

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:
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.

Accepted Answer

Being at the 80th percentile means Franklin scored higher than or equal to 80% of the test takers, not that 80 people scored below him, that he's in the bottom 20%, or that his z-score is 80.

Question 9

A major retail store has studied customer behavior and found that the distribution of time customers spend in a store per visit is symmetric with a mean equal to 17.3 minutes. Based on this information, which of the following is true?
A) The distribution is right-skewed.
B) The median is to the right of the mean.
C) The median is approximately 17.3 minutes.
D) The median is to the left of the mean.

Accepted Answer

Since the distribution is symmetric and the mean is 17.3 minutes, the median will also be centered and approximately equal to the mean, which is 17.3 minutes.

Question 10

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, which of the following statements is correct?
A) The distribution of log diameters is symmetric.
B) A log that is over 20 inches in diameter can be considered an outlier.
C) The distribution of log diameters is right-skewed.
D) The distribution is left-skewed.

Accepted Answer

The answer of At a sawmill in Oregon, a process...

Question 11

The advantage of using the interquartile range versus the range as a measure of variation is:
A) it is easier to compute.
B) it utilizes all the data in its computation.
C) it gives a value that is closer to the true variation.
D) it is less affected by extremes in the data.

Accepted Answer

The interquartile range (IQR) is less affected by extremes in the data because it focuses on the middle 50% of the data, ignoring outliers and extreme values that can skew the range.

Question 12

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, in a box and whisker plot, which of these four values will NOT appear?
A) 8.9 in.
B) 13.5 in.
C) 15.6 in.
D) 14.2 in.

Accepted Answer

The answer of At a sawmill in Oregon, a process...

Question 13

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?
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.

Accepted Answer

The answer of The following data reflect the number of...

Question 14

The following data reflect the number of customers who test drove new cars each day for a sample of 20 days at the Redfield Ford Dealership.  Given these data, what is the variance?
A) 0.69
B) Approximately 3.08
C) Approximately 9.52
D) Approximately 181

Accepted Answer

The answer of The following data reflect the number of...

Question 15

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, the boundaries on the box in a box and whisker plot are:
A) 8.9 in and 15.6 in.
B) 13.5 in ± 1.5 (Q3-Q1).
C) 14.2 in ± 1.5 (Q3-Q1).
D) 8.9 in and 14.2 in.

Accepted Answer

The answer of At a sawmill in Oregon, a process...

Question 16

A large retail company gives an employment screening test to all prospective employees. If a prospective employee receives a report saying that she scored at the 40th percentile:
A) she scored above the median.
B) she scored better than 40 percent of people who took the test.
C) she scored in the top 40 percent of people who took the test.
D) her z-score was a 40.

Accepted Answer

Scoring at the 40th percentile means the individual scored better than 40 percent of the people who took the test, not that they are in the top 40 percent or above the median (50th percentile). Percentiles rank the position below which a certain percentage of scores fall, and a z-score is a measure of how many standard deviations an element is from the mean, not a percentile rank.

Question 17

For ordinal data, ________ is the preferred measure of central location.
A) the mean
B) the median
C) the percentile
D) the quartile

Accepted Answer

The median is the preferred measure of central location for ordinal data because it represents the middle value in a ranked order, which aligns with the nature of ordinal data that categorizes variables in a specific order but does not quantify the difference between categories.

Question 18

Which of the following is the most frequently used measure of variation?
A) The range
B) The standard deviation
C) The variance
D) The mode

Accepted Answer

The standard deviation is the most frequently used measure of variation because it takes into account the spread of the data and the number of data points.

Question 19

The box and whisker plot CANNOT be used to identify:
A) skewedness.
B) centerness.
C) outliers.
D) symmetry.

Accepted Answer

The box and whisker plot is designed to show the distribution, range, and skewness of a dataset, and it can highlight outliers and symmetry/asymmetry. However, it does not directly provide a measure of "centerness" or the central tendency (like mean or median) in a way that distinguishes between different types of central tendency.

Question 20

The following data reflect the number of customers who test drove new cars each day for a sample of 20 days at the Redfield Ford Dealership.  Given these data, what is the interquartile range?
A) 3
B) 7
C) 4
D) 14

Accepted Answer

The answer of The following data reflect the number of...

Quiz 3: Describing Data Using Numerical Measures

The following data reflect the number of customers who test drove new cars each day for a sample of 20 days at the Redfield Ford Dealership. Given these data, what is the range?

If a data set has 740 values that have been sorted from low to high, which value in the data set will be the 20th percentile?

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. Based on these data, what is the standard deviation?

Which of the following measures is not affected by extreme values in the data?

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?

If a data set has 1,133 sorted values, what value corresponds to the 3rd quartile?

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?

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:

A major retail store has studied customer behavior and found that the distribution of time customers spend in a store per visit is symmetric with a mean equal to 17.3 minutes. Based on this information, which of the following is true?

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, which of the following statements is correct?

The advantage of using the interquartile range versus the range as a measure of variation is:

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, in a box and whisker plot, which of these four values will NOT appear?

The following data reflect the number of customers who test drove new cars each day for a sample of 20 days at the Redfield Ford Dealership. Given these data, what is the variance?

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, the boundaries on the box in a box and whisker plot are:

A large retail company gives an employment screening test to all prospective employees. If a prospective employee receives a report saying that she scored at the 40th percentile:

For ordinal data, ________ is the preferred measure of central location.

Which of the following is the most frequently used measure of variation?

The box and whisker plot CANNOT be used to identify:

The following data reflect the number of customers who test drove new cars each day for a sample of 20 days at the Redfield Ford Dealership. Given these data, what is the interquartile range?