AP Stats Mid Year

A certain middle school opens at 7 A.M., and classes begin at 8 A.M. A sociologist gathered data on the number of minutes after 7 A.M. that a student arrives at school and the number of friends the student has on social media. The correlation between the two variables indicated a strong negative relationship. Which of the following is an appropriate interpretation of the correlation?

• Students who arrive early to school have more friends on social media.

• Students who arrive late to school have more friends on social media.

• Having a lot of friends on social media causes a student to arrive late for school.

• As the number of minutes of arriving after 7 A.M. increases, the number of friends on social media tends to increase.

• As the number of minutes of arriving after 7 A.M. increases, the number of friends on social media tends to decrease.

The following is a residual plot from a regression of a variable with the independent variable x. Based on the plot, is it reasonable to conclude that a linear model is appropriate?

• Yes, because the plot shows no apparent pattern.

• Yes, because the points in the plot display less variation as x increases.

• Yes, because the sum of the residuals is close to zero.

• No, because the plot shows no apparent pattern.

• No, because the points in the plot display more variation as x increases.

The following scatterplot shows a company's monthly sales, in thousands of dollars, versus monthly advertising dollars spent, in thousands of dollars. Which of the following points is most likely a high-leverage point with respect to a regression of monthly sales versus advertising dollars?

• (5.1, 105)

• (5.8, 110)

• (6.0, 125)

• (6.7, 108)

• (6.8, 123)

The following scatterplot shows the ages, in years, of 12 of the wealthiest people in the world along with their net worth, in billions of dollars. The data point at age 83 is labeled Q. Suppose point Q is removed from the data set. Which of the following is likely not affected by the removal?

• The correlation coefficient

• The sign of the slope coefficient

• The value of the slope coefficient

• The sum of the squared residuals

• The net worth intercept

Identify the sampling method:

Every fifth person boarding a plane is searched thoroughly.

• SRS

• Stratified

• Cluster

• Systematic

• Voluntary Response

Identify the sampling method:

At a local community College, five math classes are randomly selected out of 20 and all of the students from each class are interviewed.

• SRS

• Stratified

• Cluster

• Systematic

• Convenience

Identify the sampling method:

A community college student interviews the first 100 students to enter the building to determine the percentage of students that own a car.

• SRS

• Stratified

• Cluster

• Convenience

• Voluntary Response

The names of 70 contestants are written on 70 cards, The cards are placed in a bag, and three names are picked from the bag.

• SRS

• Systematic

• Stratified

• Cluster

• Convenience

Which of the following is the best estimate of the standard deviation of the distribution in the figure?

• 18

• 9

• 54

• 97

• 106

A company determines the mean and standard deviation of the employees' salaries in one year. What is the best description of the standard deviation?

• Approximately the median distance between the individual salaries of employees and the mean of every employee's salary.

• The amount of money separating the highest salary from the lowest salary when considering the middle 50% of the distribution.

• The amount of money separating the highest salary from the lowest salary when considering all employees.

• The distance between the salary of an employee and the mean salary of all the employees.

• Approximately the mean distance between the individual salaries of employees and the mean of all employees' salaries.