Chapter 9 Multiple Choice Practice AP Stats

• 4.83 inches

• 5.18 inches

• 6.04 inches

• 8.93 inches

• The standard deviation cannot be computed from the given information.

The EPA requires that the exhaust of each model of motor vehicle be tested for the level of several pollutants. The level of oxides of nitrogen (NOX) in the exhaust of one light truck model was found to vary among individual trucks according to an approximately Normal distribution with mean μ = 1.45 grams per mile driven and standard deviation σ = 0.40 gram per mile. Which of the following best estimates the proportion of light trucks of this model with NOX levels greater than 2 grams per mile?

• 0.0228

• 0.0846

• 0.4256

• 0.9154

• 0.9772

Which of the following is not correct about a standard Normal distribution?

• The proportion of scores that satisfy 0 < z < 1.5 is 0.4332.

• The proportion of scores that satisfy z < -1.0 is 0.1587

• The proportion of scores that satisfy z > 2.0 is 0.0228

• The proportion of scores that satisfy z < 1.5 is 0.9332

• The proportion of scores that satisfy z > -3.0 is 0.9938

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 first quartile

• between the first quartile and the median

• between the median and the third quartile

• between the third quartile and the maximum

• at the mean score for all students

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 his tip distribution?

• $2.90, $0.30

• $2.90, $2.30

• $9.00, $3.00

• $11.00, $2.00

• $2.00, $0.90

Scores on the ACT college entrance exam follow a bell-shaped distribution with mean 21 and standard deviation 5. Wayne's standardized score on the ACT was -0.6. What was Wayne's actual ACT score?

• 3

• 13

• 16

• 18

• 24

The weights of laboratory cockroaches follow 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 this Normal curve corresponds to

• 84 grams

• 82 grams

• 78 grams

• 76 grams

• 74 grams

About what proportion of the cockroaches will have weights greater than 83 grams?

• 0.0228

• 0.0668

• 0.1587

• 0.9332

• 0.0772

A different species of cockroach has weights that are approximately Normally distributed 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 weight for this species of cockroaches?

• 4.6

• 5.0

• 6.2

• 4.0

• Cannot determine without more information

For the three histograms pictured here, which of the following correctly orders the histograms from the one with the smallest proportion of data above its mean to the one with the largest proportion of data above its mean?

• J, K, L

• J, L, K

• K, L, J

• L, K, J

• All three histograms have the same proportion of data above their respective means.