Question 1

Either vertical or horizontal bars can be used when constructing a bar graph.

Accepted Answer

Vertical or horizontal bars can be used when constructing a bar graph depending on the presentation preference or the nature of the data being presented.

Question 2

Chebyshev's rule applies to qualitative data sets, while the empirical rule applies to quantitative
data sets.

Accepted Answer

Chebyshev's rule and empirical rule both apply to quantitative data sets, not qualitative data sets.

Question 3

The range is an insensitive measure of data variation for large data sets because two data sets can have the same range but be vastly different with respect to data variation.

Accepted Answer

The range only looks at the difference between the maximum and minimum values in a data set, which can be misleading when there are outliers or extreme values. Two data sets can have the same range but very different distributions and levels of variation.

Question 4

All class intervals in a histogram have the same width.

Accepted Answer

This is true. In a histogram, the width of all class intervals is the same, in order to create a proportional representation of the data. This also allows for easy comparison between different bars in the histogram.

Question 5

For large data sets, a stem-and-leaf display is a better choice than a histogram.

Accepted Answer

For large data sets, a histogram is a better choice than a stem-and-leaf display as it can display the distribution of data more clearly and accurately. A stem-and-leaf display can be useful for smaller data sets or for presenting data with specific values that need to be emphasized.

Question 6

Many firms use on-the-job training to teach their employees computer programming. Suppose you work in the personnel department of a firm that just finished training a group of its employees
To program, and you have been requested to review the performance of one of the trainees on the final test that was given to all trainees. The mean of the test scores is 70. Additional information indicated that the median of the test scores was 80. What type of distribution most likely describes the shape of the test scores?
A) symmetric
B) unable to determine with the information given
C) skewed to the left
D) skewed to the right

Accepted Answer

The answer of Many firms use on-the-job training to teach...

Question 7

Many firms use on-the-job training to teach their employees computer programming. Suppose you work in the personnel department of a firm that just finished training a group of its employees to program, and you have been requested to review the performance of one of the trainees on the
Final test that was given to all trainees. The mean and standard deviation of the test scores are 84 and 5, respectively, and the distribution of scores is mound-shaped and symmetric. What percentage of test-takers scored better than a trainee who scored 69?
A) approximately 95%
B) approximately 97.5%
C) approximately 84%
D) approximately 100%

Accepted Answer

The answer of Many firms use on-the-job training to teach...

Question 8

What number is missing from the table? $$\begin{array} { | l | c | c | } 
\hline { \begin{array} { c } 
\text { Year in } \
\text { College }
\end{array} } & \text { Frequency } & \begin{array} { c } 
\text { Relative } \
\text { Frequency }
\end{array} \
\hline \text { Freshman } & 600 & .30 \
\hline \text { Sophomore } & 560 & .28 \
\hline \text { Junior } & & .22 \
\hline \text { Senior } & 400 & .20 \
\hline
\end{array}$$
A) 520
B) 440
C) 480
D) 220

Accepted Answer

The answer of What number is missing from the table?...

Question 9

The pie chart shows the classifications of students in a statistics class. What percentage of the class consists of freshman, sophomores, and juniors?
A) 44%
B) 14%
C) 86%
D) 54%

Accepted Answer

The answer of  
The pie chart shows the classifications...

Question 10

In practice, the population mean µ is used to estimate the sample mean $\bar{x}$.

Accepted Answer

In practice, the sample mean $\bar{x}$ is used to estimate the population mean µ, not the other way around.

Question 11

On a given day, the price of a gallon of milk had a mean price of $2.16 with a standard deviation of $0.07. A particular food store sold milk for $2.09/gallon. Interpret the z-score for this gas station.
A) The milk price of this food store falls 1 standard deviation below the milk gas price of all food stores.
B) The milk price of this food store falls 7 standard deviations above the mean milk price of all food stores.
C) The milk price of this food store falls 1 standard deviation above the mean milk price of all food stores.
D) The milk price of this food store falls 7 standard deviations below the mean milk price of all food stores.

Accepted Answer

The z-score for this gas station is (2.09 - 2.16) / 0.07 = -1. This means that the milk price of this food store falls 1 standard deviation below the mean milk price of all food stores.

Question 12

According to the empirical rule, z-scores of less than -3 or greater than 3 occur very infrequently for data from a mounded and symmetric distribution

Accepted Answer

The empirical rule states that approximately 99.7% of data falls within 3 standard deviations of the mean for a mounded and symmetric distribution, which means that z-scores of less than -3 or greater than 3 occur very infrequently. So, the statement is true.

Question 13

Both Chebyshev's rule and the empirical rule guarantee that no data item will be more than four standard deviations from the mean.

Accepted Answer

Chebyshev's rule applies to any distribution, guaranteeing that at least $1 - \frac{1}{k^2}$ of the data lies within k standard deviations from the mean for any k > 1, but it does not guarantee that no data item will be more than four standard deviations from the mean. The empirical rule, specific to normal distributions, suggests that about 68%, 95%, and 99.7% of the data lie within one, two, and three standard deviations from the mean, respectively, but it also does not make guarantees beyond three standard deviations.

Question 14

A larger standard deviation means greater variability in the data.

Accepted Answer

A larger standard deviation indicates that the data points are more spread out from the mean, indicating greater variability.

Question 15

Box plots are used to detect outliers in qualitative data sets, while z-scores are used to detect outliers in quantitative data sets.

Accepted Answer

Box plots can be used to detect outliers in quantitative data sets as well as qualitative data sets. Z-scores are a quantitative measure that can be used to identify outliers in a quantitative data set.

Question 16

Many firms use on-the-job training to teach their employees computer programming. Suppose you work in the personnel department of a firm that just finished training a group of its employees to program, and you have been requested to review the performance of one of the trainees on the
Final test that was given to all trainees. The mean and standard deviation of the test scores are 82 and 5, respectively. Assuming nothing is known about the distribution, what percentage of test-takers scored above 92?
A) approximately 97.5%
B) approximately 2.5%
C) at most 25%
D) at least 75%

Accepted Answer

Using Chebyshev's inequality, at most 25% of test-takers scored above 92, as 92 is 2 standard deviations above the mean.

Question 17

Each year advertisers spend billions of dollars purchasing commercial time on network television. In the first 6 months of one year, advertisers spent $1.1 billion. Who were the largest spenders? In a recent article, the top 10 leading spenders and how much each spent (in million of dollars) were
Listed: $$\begin{array} { l r l r } 
\text { Company A } & \$ 70.7 & \text { Company F } & \$ 24.8 \
\text { Company B } & 63.9 & \text { Company G } & 24 \
\text { Company C } & 55.7 & \text { Company H } & 22.7 \
\text { Company D } & 54.2 & \text { Company I } & 23.2 \
\text { Company E } & 30.3 & \text { Company J } & 20.1
\end{array}$$ Calculate the sample variance.
A) 3763.035
B) 1864.521
C) 2080.829
D) 389.965

Accepted Answer

The answer of Each year advertisers spend billions of dollars...

Question 18

If a sample has mean 0 and standard deviation 1, then for every measurement x in the sample the z-score of x is x itself.

Accepted Answer

This is true because the z-score formula is z = (x - mean) / standard deviation. If the mean is 0 and the standard deviation is 1, then the formula simplifies to z = x - 0 / 1 = x.

Question 19

Which of the following statements could be an explanation for the presence of an outlier in the data?
A) The measurement belongs to a population different from that from which the rest of the sample was drawn.
B) The measurement may be correct and from the same population as the rest but represents a rare event. Generally, we accept this explanation only after carefully ruling out all others.
C) The measurement is incorrect. It may have been observed, recorded, or entered into the computer incorrectly.
D) All of the above are explanations for outliers.

Accepted Answer

Outliers in data can arise due to various reasons: they might be the result of a measurement from a different population (A), a correct but rare measurement from the same population (B), or errors in observation, recording, or data entry (C). Therefore, all the given options are valid explanations for the presence of outliers in a dataset.

Question 20

Class relative frequencies must be used, rather than class frequencies or class percentages, when constructing a Pareto diagram.

Accepted Answer

A Pareto diagram typically uses class frequencies or percentages to show the relative importance of different categories, not class relative frequencies.

Quiz 2: Methods for Describing Sets of Data

Either vertical or horizontal bars can be used when constructing a bar graph.

Chebyshev's rule applies to qualitative data sets, while the empirical rule applies to quantitative data sets.

The range is an insensitive measure of data variation for large data sets because two data sets can have the same range but be vastly different with respect to data variation.

All class intervals in a histogram have the same width.

For large data sets, a stem-and-leaf display is a better choice than a histogram.

The pie chart shows the classifications of students in a statistics class. What percentage of the class consists of freshman, sophomores, and juniors?

In practice, the population mean µ is used to estimate the sample mean $\bar{x}$ .

On a given day, the price of a gallon of milk had a mean price of $2.16 with a standard deviation of $0.07. A particular food store sold milk for $2.09/gallon. Interpret the z-score for this gas station.

According to the empirical rule, z-scores of less than -3 or greater than 3 occur very infrequently for data from a mounded and symmetric distribution

Both Chebyshev's rule and the empirical rule guarantee that no data item will be more than four standard deviations from the mean.

A larger standard deviation means greater variability in the data.

Box plots are used to detect outliers in qualitative data sets, while z-scores are used to detect outliers in quantitative data sets.

If a sample has mean 0 and standard deviation 1, then for every measurement x in the sample the z-score of x is x itself.

Which of the following statements could be an explanation for the presence of an outlier in the data?

Class relative frequencies must be used, rather than class frequencies or class percentages, when constructing a Pareto diagram.

Quiz 2: Methods for Describing Sets of Data

Either vertical or horizontal bars can be used when constructing a bar graph.

Chebyshev's rule applies to qualitative data sets, while the empirical rule applies to quantitative data sets.

The range is an insensitive measure of data variation for large data sets because two data sets can have the same range but be vastly different with respect to data variation.

All class intervals in a histogram have the same width.

For large data sets, a stem-and-leaf display is a better choice than a histogram.

The pie chart shows the classifications of students in a statistics class. What percentage of the class consists of freshman, sophomores, and juniors?

In practice, the population mean µ is used to estimate the sample mean xˉ\bar{x}xˉ .

On a given day, the price of a gallon of milk had a mean price of $2.16 with a standard deviation of $0.07. A particular food store sold milk for $2.09/gallon. Interpret the z-score for this gas station.

According to the empirical rule, z-scores of less than -3 or greater than 3 occur very infrequently for data from a mounded and symmetric distribution

Both Chebyshev's rule and the empirical rule guarantee that no data item will be more than four standard deviations from the mean.

A larger standard deviation means greater variability in the data.

Box plots are used to detect outliers in qualitative data sets, while z-scores are used to detect outliers in quantitative data sets.

If a sample has mean 0 and standard deviation 1, then for every measurement x in the sample the z-score of x is x itself.

Which of the following statements could be an explanation for the presence of an outlier in the data?

Class relative frequencies must be used, rather than class frequencies or class percentages, when constructing a Pareto diagram.

In practice, the population mean µ is used to estimate the sample mean $\bar{x}$ .