AP Stats Unit 2 Practice

Jorge's score on Exam 1 in his statistics class was at the 64th percentile of the scores for all students. His score falls

• between the minimum and the first quartile

• between the first quartile and the median

• between the median and the third quartile

• between the third quartile and the maximum

When Sam goes to a restaurant, he always tips the server $2 plus 10% of the cost of the meal. If Sam's distribution of meal costs has a mean of $9 and a standard deviation of $3, what are the mean and standard deviation of the distribution of tips?

• $2.90, $0.30
• $2.90, $2.30
• $11.00, $2.00
• $2.00, $0.90

Scores on the ACT college entrance exam follow a bell-shaped distribution with mean 18 and standard deviation 6. Wayne's standardized score on the ACT was -0.5. What was Wayne's actual ACT score.

• 5.5
• 12
• 15
• 17.5

George has an average bowling score of 180 and bowls in a league where the average for all bowlers is 150 and the standard deviation is 20. Bill has an average bowling score of 190 and bowls in a league where the average is 160 and the standard deviation is 15. Who ranks higher in his own league, George or Bill?

• Bill, because his 190 is higher than George's 180.
• Bill, because his standardized score is higher than George's.
• Bill and George have the same rank in their league because both are 30 pins above the mean.
• George, because his standardized score is higher than Bill's.

What is the interquartile range for the distribution of absences as shown in the cumulative relative frequency graph?

• 1
• 3
• 2
• 5

Two measures of center are marked on the density curve shown. Which of the following is correct?

• The median is at the yellow line and the mean is at the red line
• The median is at the red line and the mean is at the yellow line
• The mode is at the red line and the median is at the yellow line
• The mode is at the yellow line and the median is at the red line

The weights of laboratory cockroaches follows a Normal distribution with mean 80 grams and standard deviation 2 grams. The following figure is the Normal curve for the distribution of weights.
Point C on the Normal curve corresponds to

• 84 grams
• 74 grams
• 78 grams
• 82 grams

The weights of laboratory cockroaches follows a Normal distribution with mean 80 grams and standard deviation 2 grams. About what percent of the cockroaches will have weights between 76 and 84 grams?

• 99.7%

• 68%

• 34%

• 95%

The weights of laboratory cockroaches follows a Normal distribution with mean 80 grams and standard deviation 2 grams. About what proportion of cockroaches will have weights greater than 83 grams?

• 0.0228

• 0.1587

• 0.0772

• 0.0668

A different species of cockroaches has weights that follow a Normal distribution with a mean of 50 grams. After measuring the weights of many of these cockroaches, a lab assistant reports that 14% of the cockroaches weigh more than 55 grams. Based on this report, what is the approximate standard deviation of weights for this species of cockroaches?

• 4.6
• 14.0
• 5.0
• 6.2