AP Statistics Midterm Exam Review
1. In a random sample of 39 adults, each adult was asked to report the amount of his or her last grocery bill
in dollars. The stem­and­leaf plot of the results is shown here.
1
99
2
023
Key: 2
6
means the bill was $26
2
568
3
003
3
679
4
12244
4
5556667778
5
0012334
5
55
6
0
a. How would you describe the distribution?
b. What is the 5 number summary of the distribution?
c. Convert the stem­and­leaf plot into a box plot.
2. Consider the following set of data: 30, 35, 35, 45, 55, 60, 60, 75, 90. If you subtract 20 from each value in
the data set how does this change the original mean and standard deviation?
3. The distribution of raw scores on a Biology final is approximately normal with mean 70 and standard
deviation 10. What approximate percent of students have a raw score that is less than 55?
4. The median of all 21 students in a statistics class is 17 years. A 16 year old student withdraws from the
class and a 12 year old enrolls. What is the new approximate median age of the students in the class?
5. The midterm and final test grades of a sample of 11 Trig students were recorded. From the regression
equation the model suggests that for every increase of one point on the midterm, the final score tends to
increase on average about .0.85 points. The model also suggests that if one were to score zero points on the
midterm they would earn 9.55 points on the final exam. Knowing this, what is the regression equation that will
match this information?
6. The model suggests that each decade a person drinks removes 2.2 years from your life. In
this model y is life span and x is decades spent drinking. If your friend has been drinking for 11 years what is
her approximate predicted life span?
AP Statistics Midterm Exam Review
7. A music director is interested in studying whether or not music affects longevity of studying. To do this the
director gave a list of 1000 vocabulary words to 30 students. 15 of those students studied while listening to
music and the other studied without music. The director recorded how much time students spent studying the
words straight and stopped measuring once students were distracted or stopped studying. Describe the
factors, levels, conditions, and response variable for this study.
8. The distribution of SAT II Spanish scores is approximately normal with mean 560 and standard deviation
80. The probability that 100 randomly selected students will have a mean SAT II Spanish score greater than
650 is approximately what?
9. The table below shows the proportion of households in America and the number of female children that
they have.
# of female children
0
1
2
3
4 or more
Proportion of Households
0.58
0.31
0.09
0.01
0.01
What is the approximate probability that a random sample of 10 US households will have a mean of 2 female
children or less?
10. The distribution of heights of Olympic Long Jump Gold Medal Champions is approximately normal with
mean 73 inches and standard deviation 6 inches and the distribution of heights of the Olympic Long Jump
Silver Medal Champions is also approximately normal with mean 69 inches and standard deviation 5. What is
the probability that the sum of the heights is more than 151 inches?
11. The table below shows the amount of exercise that 3 age groups get on average per week.
Less than 3 hours
20­35
36­50
Total
440
650
1090
3­5 hours
560
250
810
Greater than 5 hours
300
100
400
total
1300
1000
2300
a. What is the probability that a person chosen randomly is in the lower age bracket and exercises greater than 5
hours per week?
b. What is the probability that a person is 20­35 given that he exercises 3­5 hours per week?
AP Statistics Midterm Exam Review
c. What is the probability that a person chosen at random will exercise 5 hours or less?