AP Statistics
Chapter 4 Review
Name:____________________________________Period:___
For problems #1-4, use the following information: The length of human pregnancies from conception to birth
varies according to a distribution that is approximately normal with mean 245 days and standard deviation
12 days.
1. What percent of pregnancies last less than 230 days?
2. What percent of pregnancies last between 235 to 262 days?
3. How long do the longest 15% of pregnancies last?
4. How long do the shortest 10% of pregnancies last?
5. The following data represents the number of points awarded in the opening round of the floor exercise
for 20 participants at the Olympics games this summer by one of the judges:
1 2 5 3 2 5 3 8 4 6 6 2 8 1 9 5 5 7 4 5.
Find the 5 # summary, create a box plot, determine the mean, median, standard deviation, and variance
for this data set. Also find the IQR, and determine if there are any outliers.
6. What percentage of the data in a normal distribution falls within 3 standard deviations of the mean? 1
standard deviation of the mean? 2 standard deviation of the mean?
7. After completing your AP English test, you find out that you scored 1.76 standard deviations away from
the mean. The mean grade on the test was a 56 with a standard deviation of 4.7. What grade did you
make on the test?
8. Scores on the Harvard Intelligence Scale for the 18-24 age group are approximately normally distributed
with mean=210 and standard deviation=40. How many standard deviations is 180 from the mean?
AP Statistics
Chapter 4 Review
Name:____________________________________Period:___
9. Here are the annual numbers of deaths from tornadoes in the United States from 2000-2010.
43
18
39
56
78
58
49
36
57
90
Calculate a 20% trimmed mean, and find the standard deviation for this new data set.
10. John Doe decided to record the speeds of cards driving past his house, where the speed limit reads 30
mph. The mean of 60 readings was 36.27 mph with a standard deviation of 2.46 mph.
a. How many standard deviations from the mean would a car going under the speed limit be?
b. Which would be more unusual, a car traveling 45 mph or 29 mph?
c. To see how many cars are speeding, John subtracts 30 from all the speeds. What is the mean
speed now? What is the standard deviation now?
d. John’s friend in Germany wants to study the speeds, so John converts them to kilometers by
multiplying all the speeds by 1.609 km per hour. What is the mean now? What is the standard
deviation?
Other things to study……
Vocabulary is always important
Previous material is always fair game
Look back over previous quizzes and assignments
Be able to match graphs to their data, data to their graphs, and graphs to corresponding graphs