Big AP Stats Review

An SRS of 100 teachers showed that 64 owned smartphones.  An SRS of 100 students showed that 80 owned smartphones.  Let pₑ be the proportion of all teachers who own smartphones, and let pₓ be the proportion of all students who own smartphones.  A 95% confidence interval for the difference pₑ - pₓ is 

• (0.264, 0.056)

• (0.098, 0.222)

• (-0.222, -0.098)

• (-0.283, -0.038)

If P(A) = 0.24 and P(B) = 0.52 and A and B are independent, what is P(A or B)?

• 0.1248

• 0.28

• 0.6352

• 0.76

In your top dresser drawer are 6 blue socks and 10 grey socks, unpaired and mixed up.  One dark morning you pull two socks from the drawer (without replacement, of course!)  What is the probability that the two socks match?

• 0.075

• 0.375

• 0.450

• 0.500

A simple random sample of 1000 Americans found that 62% were satisfied with the service provided by the dealer from which they bought their car.  A simple random sample of 1000 Canadians found that 59% were satisfied with the service provided by the dealer from which they bought their car.  The sampling variability associated with these statistics is

• exactly the same

• not exactly the same, but very close

• much smaller for the sample of Canadians because the population of Canad is much smaller than that of the United States, hence the sample is a larger proportion of the population.

• smaller for the sample of Canadians because the percent satisfied was smaller than that of Americans.

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.

The heights of adult women are approximately normally distributed about a mean of 65 inches with a standard deviation of 2 inches. If Bella is at the 87th percentile in height for adult women, then her height, in inches, is closest to

• 63

• 67

• 66

• 72

• 70

The graph shows the distribution of scores of 30 students on a mathematics test. Based on the histogram, which statement must be true?

• The lowest test score is 41%.

• The highest test score is 100%.

• The mean test score is between 81% and 90%.

• The median test score is not greater than 80%.

• The lower quartile of the test scores is greater than 60%.

In a certain school, students can choose whether to eat in the school’s cafeteria. A reporter working for the school’s newspaper polled students on their reactions to changes in the menu at the cafeteria. For each student leaving the cafeteria in one 20-minute time period, the reporter used a die to determine whether to stop the student and ask how he or she felt about the new menu. In the reporter’s article it was stated that a random sample of the students showed that 23% of the school’s student population was happy with the new menu. Which of the following statements is true?

• Because each student leaving the cafeteria was randomly selected and could choose to answer or not, this is a random sample of the student population, and the 23% is an accurate measurement of the school population’s view of the new menu.

• Because students self-selected whether to eat in the cafeteria, the sampling method might be biased and the sample might not be representative of all students in the school.

• The survey would have been more effective if the reporter had collected the data in one 10-minute time period rather than in one 20-minute time period.

• The survey would have been more effective if students who cared about the food could have called the reporter to tell how they felt about the new menu, so that only students with opinions on the subject would have been surveyed.

• Because no treatment was imposed on the students eating in the cafeteria, one cannot make any conclusions about the new menu.

The boys and girls basketball teams at a high school had their heights measured at practice. The following data was recorded for their heights. What can you conclude from the distributions?

• The girls have a larger median and a larger range in heights.

• The boys had a smaller median height than the girls; however, the boys had a larger range of heights.

• The median height for the boys and the girls is the same; however, the girls have a larger range.

• The median height for the boys is larger; however, the girls have a larger range.

• No information can be concluded from the distribution since there is no key included.