AP Statistics Chapter 4 Review

A teacher is teaching two AP Statistics classes. On the final exam, the 25 students in the first class averages 87, while the 30 students in the second class averages 98. If the teacher combines the classes, what will the average final exam score be?

• 92

• 92.5

• 93

• 94.5

• 95

The number of siblings was recorded for each student of a group of 80 students. some summary statistics and a histogram displaying the results are shown below. An outlier is often defined as a number that is more than 1.5 times the interquartile range below the first quartile or above the third quartile. Using the definition of an outlier and the given information, which of the following can be concluded?

• The median is greater than the mean, and the distribution has no outliers.

• The median is greater than the mean, and the distribution has only one outlier.

• The median is greater than the mean, and the distribution has two outliers.

• The median is less than the mean, and the distribution has two outliers.

• The median is less than the mean, and the distribution only has one outlier.

The histogram shows the ages of cars in the parking lot at a local high school. Which of the following statements are TRUE? I. The mean age is greater than the median age.II. The median age is greater than the mean age.III. The median is between 6 and 8 years.

• I only

• II only

• III only

• I and II

• II and III

Which of the following are likely to be true of this distribution? (Select all that may be true).

• Mean = 3, Median = 3

• Mean = 3.5, Median = 4

• Mean = 4, Median = 3.5

•  Mean = 3.5, Median = 3.5

• Mean = 3, Median = 2

Fastball speeds in collegiate baseball are normally distributed with a mean of 86 mph and a standard deviation of 4 mph. Suppose that major league scouts will only consider pitching prospects who can throw a fastball at least 90 mph. What percentage of the pitchers will be considered?

• 1.2%

• 7.7%

• 14.7%

• 15.9%

• 44.4%

Kitchen appliances don’t last forever. The lifespan of all microwave ovens sold in the United States is approximately Normally distributed with a mean of 9 years and a standard deviation of 2.5 years. What percentage of the ovens last more than 10 years?

• 11.5%

• 34.5%

• 65.5%

• 69%

• 84.5%

The following statistics were produced at the end of a week at a weight loss center indicating pounds lost.

 

Mean = 5 lbs                           Median = 7 lbs                                    Mode = 4 lbs

First Quartile = 2 lbs               Third Quartile = 8.5 lbs                      Standard Deviation = 0.5 lbs

 

Which of the following statement(s) are correct?

 

I. One quarter of weight watchers lost 2 pounds or less.

II. The middle 50% of the weight waters lost between 2 and 8.5 pounds.

III. The most common weight loss waas 4 pounds.

• I only

• II only

• III only

• I and III

• I, II, and III

The distribution of weights of female college cross-country runners is approximately normal with mean 122 pounds and standard deviation 8 pounds. Which of the following is closest to the percent of the runners who weigh between 114 pounds and 138 pounds?

• 18%

• 32%

• 68%

• 82%

• 95%

A student obtained a z-score of -1.40 on a national test for which the mean score was 500 and the standard deviation was 50. The student’s actual test score was

• 570

• 430

• 564

• 640

• 450

The mean age (at inauguration) of all U.S. Presidents is approximately Normally distributed with a mean of 54.6.  Barack Obama was 47 when he was inaugurated, which is the 11th percentile of the distribution.  Which of the following is closest to the standard deviation of presidents’ ages?

• -9.20

• -6.18

• 6.18

• 7.60

• 9.20