Question 1

Prices per share of the 20 most actively traded stocks on the New York Stock Exchange in October, 2012. A histogram for these data are shown below.
The data can be described as

Accepted Answer

The histogram shows a longer tail to the right, indicating that the data are skewed to the right. There is a single bar that is noticeably taller than the others, indicating a large positive outlier. Therefore, the best choice is D – the data are skewed to the right with a large positive outlier.

Question 2

A manufacturer of cable wire periodically selects samples to monitor the process. A sample of ten wires is selected and the diameters (in cm.) are 0.493, 0.534, 0.527, 0.511,0.565, 0.559, 0.519, 0.562, 0.551, and 0.530. The mean diameter is

Accepted Answer

To find the mean diameter, we need to add up all the diameters and divide by the total number of wires:

(0.493 + 0.534 + 0.527 + 0.511 + 0.565 + 0.559 + 0.519 + 0.562 + 0.551 + 0.530) ÷ 10 = 0.535

Therefore, the mean diameter is 0.535 cm, which corresponds to answer choice B.

Question 3

Prices per share of the 20 most actively traded stocks on the New York Stock Exchange in October, 2012. Summary statistics for these data are shown below. The
IQR for this set of dataset is $$\begin{array} { | c | c | c | c | c | c | c | } 
\hline \text { Min } & \text { Q1 } & \text { Median } & \text { Q3 } & \text { Max } & \text { Mean } & \text { SD } \
\hline 2.0 & 7.5 & 15.5 & 34.5 & 85.0 & 4.67 & 20.9 \
\hline
\end{array}$$

Accepted Answer

The IQR (Interquartile Range) is calculated as Q3 - Q1, which is 34.5 - 7.5 = 27.

Question 4

A magazine that publishes product reviews conducted a survey of teenagers' preferences for cell phones. Three brands of cell phone designed specifically with teens
In mind were the focus of the study. The table summarizes responses by brand and
Gender. What percent of teenagers who preferred the BlackJack II were males? $$\begin{array} { | l | l | l | } 
\hline \text { Cell Phone } & \text { Male } & \text { Female } \
\hline \text { LG Rumor } & 55 & 87 \
\hline \text { Sidekick LX } & 99 & 150 \
\hline \text { BlackJack II } & 196 & 113 \
\hline
\end{array}$$

Accepted Answer

To find the percent of teenagers who preferred the BlackJack II and were males, divide the number of males who preferred BlackJack II by the total number of teenagers who preferred BlackJack II, then multiply by 100. For BlackJack II, males = 196, females = 113, so total = 196 + 113 = 309. The percentage is (196 / 309) * 100 ≈ 63%.

Question 5

US public debt per capita historical data for the years 2009-2013 yields the following scatterplot:  The equation of the regression line is predicted $($ Debt per capita $\$ \mathrm {~K} ) = - 6,975 + 3.49 \times ($ Debt Year $)$ with $R ^ { 2 } = 99.5 \%$. Which of the following statements is true?

Accepted Answer

A) About 99.5% of the variability in debt per capita is explained by the model: This statement is true because the coefficient of determination, $R ^ { 2 } = 99.5 \% $, measures the proportion of variability in the debt per capita that is explained by the regression model.

B) On average, debt per capita increases $3.49K per year: This statement is true because the regression equation shows that for each year, the predicted debt per capita increases by $3.49K.

C) The response variable is "year": This statement is false because the year is the explanatory variable, not the response variable. The response variable is the debt per capita.

Therefore, the correct answer is D: Both A and B.

Question 6

Real estate agencies keep track of housing prices in a given area. Suppose they also provide their clients with quarterly median selling prices for homes in a given area for the
Past three year period. These data are

Accepted Answer

The data provided by the real estate agencies is a time series, as it tracks the changes in median selling prices over a period of three years. It is not cross-sectional data, which would involve a snapshot of data at a specific point in time, or categorical data, which would involve grouping data into categories. It is also not nominal or ordinal data, which would involve assigning categories or ranks to the data.

Question 7

An advocacy group is investigating whether gender has an effect on job category in large investment firms. She surveyed a sample of firms with the results shown below.
Which of the following statements is true about gender and job category?

Accepted Answer

The chart clearly shows that a greater percentage of males (46%) are executives compared to females (38%). Therefore, A is the correct answer. B is incorrect as the chart shows the opposite. C is incorrect as the chart clearly shows a difference in job category based on gender. D is not supported by the data as the percentages for clerical jobs are very similar for males and females. E is not applicable as the segmented bar chart is an appropriate way to display these data.

Question 8

A manufacturer of cable wire periodically selects samples to monitor the process. A sample of ten wires is selected and the diameters (in cm.) are 0.493, 0.534, 0.527, 0.511,0.565, 0.559, 0.519, 0.562, 0.551, and 0.530. The standard deviation is

Accepted Answer

The answer of A manufacturer of cable wire periodically selects...

Question 9

A magazine that publishes product reviews conducted a survey of teenagers' preferences for cell phones. Three brands of cell phone designed specifically with teens
In mind were the focus of the study. The table summarizes responses by brand and
Gender. What percent of teenagers preferred LG Rumor? $$\begin{array} { | l | l | l | } 
\hline \text { Cell Phone } & \text { Male } & \text { Female } \
\hline \text { LG Rumor } & 55 & 87 \
\hline \text { Sidekick LX } & 99 & 150 \
\hline \text { BlackJack II } & 196 & 113 \
\hline
\end{array}$$

Accepted Answer

To find the percent of teenagers who preferred LG Rumor, add the number of males and females who preferred it (55 + 87 = 142) and divide by the total number of respondents (55 + 87 + 99 + 150 + 196 + 113 = 700). Then, (142 / 700) * 100% = 20.29%, which rounds to 20%.

Question 10

The following scatterplot shows monthly sales figures (in units) and number of months of experience on the job for a sample of 19 salespeople. Estimate the correlation.

Accepted Answer

The answer of The following scatterplot shows monthly sales figures...

Question 11

In listing a property, real estate agencies provides information on a number of variables. Which of the following variables related to property listings is categorical?

Accepted Answer

Style of Home is a categorical variable because it represents different categories or types of homes such as colonial, ranch, Victorian, etc. The other variables listed are numerical variables that represent a quantity or value. Real Estate Tax and Asking Price are continuous variables, while Number of Bedrooms and Number of Bathrooms are discrete variables.

Question 12

What scale of measurement is the type of a car (sedan, SUV, convertible, etc)?

Accepted Answer

The type of a car (sedan, SUV, convertible, etc) is an example of nominal data, as it consists of categories without any inherent order or numerical value.

Question 13

An advocacy group is investigating whether gender has an effect on job category in large investment firms. She surveyed a sample of firms with the results shown below.
The most appropriate display for these data is a $$\begin{array} { | l | l | l | } 
\hline \text { Job Category } & \text { Male } & \text { Female } \
\hline \text { Clerical / Technical } & 85 & 215 \
\hline \text { Professional Staff } & 720 & 480 \
\hline \text { Executive / Managerial } & 400 & 100 \
\hline
\end{array}$$

Accepted Answer

A segmented bar chart would be the best choice as it allows for easy comparison between the different job categories and the proportion of males and females within each category. It also allows for easy visualization of any potential gender imbalances within each category.

Question 14

An office supply chain has stores in two locations, Dayton and Scranton. One of these stores is to be closed within the coming year, and to help make the decision,
Management reviews sales data. Below are boxplots for monthly unit sales for both
Locations.  Which of the following statement is not correct?

Accepted Answer

The answer of An office supply chain has stores in...

Question 15

For families who live in apartments the correlation between the family's income and the amount of rent they pay is r = 0.60. Which is true?
I. In general, families with higher incomes pay more in rent.
II. On average, families spend 60% of their income on rent.
III. The regression line passes through 60% of the (income$, rent$) data
Points.

Accepted Answer

The correlation coefficient (r) measures the strength and direction of the linear relationship between two variables. In this case, the variable of interest is the family's income and the amount of rent they pay. The correlation coefficient of 0.60 indicates a moderate positive linear relationship, which means that as income increases, the amount of rent paid also tends to increase. However, this correlation does not imply anything about the average percentage of income spent on rent or the regression line passing through any specific data point. Therefore, only statement I is true.

Question 16

A consumer research group investigating the relationship between the price of meat (per pound) and the fat content (grams) gathered data that produced the following
Scatterplot. Which description of the association between fat content and price is more
Accurate?

Accepted Answer

The answer of A consumer research group investigating the relationship...

Question 17

A magazine that publishes product reviews conducted a survey of teenagers' preferences for cell phones. Three brands of cell phone designed specifically with teens
In mind were the focus of the study. The table summarizes responses by brand and
Gender. What percent of female teenagers preferred the Sidekick LX? $$\begin{array} { | l | l | l | } 
\hline \text { Cell Phone } & \text { Male } & \text { Female } \
\hline \text { LG Rumor } & 55 & 87 \
\hline \text { Sidekick LX } & 99 & 150 \
\hline \text { BlackJack II } & 196 & 113 \
\hline
\end{array}$$

Accepted Answer

The answer of A magazine that publishes product reviews conducted...

Question 18

A business researcher conducted a survey of 500 women to determine preferences for types of automobiles. The types are shown below along with the number of women who
Prefer that type. Which of the following charts would be appropriate for displaying these
Data? $$\begin{array} { | l | c | } 
\hline \text { Type of Automobile } & \text { No. of Female } \
\hline \text { Sedan } & 155 \
\hline \text { SUV } & 112 \
\hline \text { Van } & 125 \
\hline \text { Sports cars } & 55 \
\hline \text { Convertible } & 28 \
\hline \text { Other } & 25 \
\hline
\end{array}$$

Accepted Answer

A pie chart would be the best choice for displaying this data because it allows for easy comparison of the proportions of each type of automobile preferred by the women surveyed.

Question 19

Which is true of the data shown in the histogram? 
I. The distribution is approximately symmetric.
II. The mean and median are approximately equal.
III. The median and IQR summarize the data better than the mean and standard deviation.

Accepted Answer

The answer of Which is true of the data shown...

Question 20

The following scatterplot shows monthly sales figures (in units) and number of months of experience on the job for a sample of 19 salespeople. Describe the association
Between monthly sales and level of experience.

Accepted Answer

The scatterplot shows a generally upward trend, indicating a positive association. The points are fairly close to a straight line, indicating a moderate linear association. Therefore, B is the best choice.

Quiz 4: Correlation and Linear Regression

Prices per share of the 20 most actively traded stocks on the New York Stock Exchange in October, 2012. A histogram for these data are shown below. The data can be described as

A manufacturer of cable wire periodically selects samples to monitor the process. A sample of ten wires is selected and the diameters (in cm.) are 0.493, 0.534, 0.527, 0.511,0.565, 0.559, 0.519, 0.562, 0.551, and 0.530. The mean diameter is

Real estate agencies keep track of housing prices in a given area. Suppose they also provide their clients with quarterly median selling prices for homes in a given area for the Past three year period. These data are

An advocacy group is investigating whether gender has an effect on job category in large investment firms. She surveyed a sample of firms with the results shown below. Which of the following statements is true about gender and job category?

A manufacturer of cable wire periodically selects samples to monitor the process. A sample of ten wires is selected and the diameters (in cm.) are 0.493, 0.534, 0.527, 0.511,0.565, 0.559, 0.519, 0.562, 0.551, and 0.530. The standard deviation is

The following scatterplot shows monthly sales figures (in units) and number of months of experience on the job for a sample of 19 salespeople. Estimate the correlation.

In listing a property, real estate agencies provides information on a number of variables. Which of the following variables related to property listings is categorical?

What scale of measurement is the type of a car (sedan, SUV, convertible, etc) ?

A consumer research group investigating the relationship between the price of meat (per pound) and the fat content (grams) gathered data that produced the following Scatterplot. Which description of the association between fat content and price is more Accurate?

Which is true of the data shown in the histogram? I. The distribution is approximately symmetric. II. The mean and median are approximately equal. III. The median and IQR summarize the data better than the mean and standard deviation.

The following scatterplot shows monthly sales figures (in units) and number of months of experience on the job for a sample of 19 salespeople. Describe the association Between monthly sales and level of experience.