FAST PRACTICE
AP STATISTICS REVIEW
Given this back to back stemplot, which
of the following is incorrect
(A) The distributions have the same mean.
(B) The distributions have the same range.
(C) The distributions have the same interquartile range.
(D) The distributions have the same standard deviation.
(E) The distributions have the same variance.
A random sample of students from each of two
schools was asked how many Supreme Court
Justices they could name. The results are given in
the tow histograms:
Which school has the greater median with regard to the
number of Justices students could name, and which
school has the greater mean?
(A) Greater median: A
Greater mean: A
(B) Greater median: A
Greater mean: B
(C) Greater median: B
Greater mean: A
(D) Greater median: B
Greater mean: B
(E) Greater median: B
Equal means
Given this back-to-back stemplot, which
of the following is true?
(A) The Empirical Rule applies to both sets A and B.
(B) The median of each is approximately (120+170)/2.
(C) In one set the mean and median should be about
the same, while in the other the mean appears to
be less that the median.
(D) The ranges of the two sets are equal.
(E) The variances of the two sets are approximately the
same.
A substitute teacher was asked to keep track of
how long it took her to get to her assigned
school each morning. Here is a stem plot of the
data. Would you expect the mean to be higher or
lower than the median?
(A) Lower, because the data are skewed to the left.
(B) Lower, because the data are skewed to the right.
(C) Higher, because the data are skewed to the left.
(D) Higher, because the data are skewed to the right.
(E) Neither, because the mean would equal the median.
Which of the Following is important in
minimizing the placebo effect?
(A) Replication and randomization
(B) Replication and blinding
(C) Randomization and blinding
(D) Randomization and a control
(E) Blinding and a control
An AP Statistics teacher grades using z-scores.
On the second major exam of the marking
period, a student receives a grade with a z-score
of -1.3. What is the correct interpretation of this
grade?
(A) The student’s grade went down 1.3 points from the first exam.
(B) The student’s grade went down 1.3 points more than the average grade went down
from the first exam.
(C) The student scored 1.3 standard deviations lower on the second exam than on the first.
(D) The student score 1.3 standard deviations lower on the second exam than the class
average on the first exam.
(E) The student scored 1.3 standard deviations lower on the second exam than the class
average on the second exam.
Suppose the scores on an exam have a mean of
75 with a standard deviation of 8. If one student
has a test result with a z-score of -1.5, and a
second student has a test result with a z-score of
2.0, how many points higher was the second
student’s result than that of the first?
(A) 3.5
(B) 4
(C) 12
(D) 16
(E) 28
If heights of 3rd graders follow a normal
distribution with a mean of 52 inches and a
standard deviation of 2.5 inches, what is the z
score of a 3rd grader who is 47 inches tall?
(A) -5
(B) -2
(C) 2
(D) 5
(E) 26.2
Motor vehicle death rates per 100,000 people among the
50 states have a mean of 13.1 with a standard deviation
of 4.9, while firearm death rates per 100,000 people
among the 50 states have a mean of 12.0 with a
standard deviation of 3.7. What would be the firearm
death rate that has the same z-score as a motor vehicle
(A) 13.4
death rate of 15.0 per 100,000?
(B) 13.5
(C) 13.9
(D) 14.5
(E) 17.1
Suppose the average height of policemen is 71 inches
with a standard deviation of 4 inches, while the average
for policewoman is 66 inches with a standard deviation of
3 inches. If a committee looks at all ways of pairing up
one male with one female officer, what will be the mean
and
standard deviation for the difference in heights for
(A) Mean of 5 inches with a standard deviation of 1 inch.
the
set
of
possible
partners?
(B) Mean of 5 inches with a standard deviation of 3.5 inches.
(C) Mean of 5 inches with a standard deviation of 5 inches.
(D) Mean of 68.5 inches with a standard deviation of 1 inch.
(E) Mean of 68.5 inches with a standard deviation of 3.5 inches.
The distribution of heights of male high school
students has a mean of 68 inches and variance of
1.52 square inches. The distribution of female high
school students has a mean of 66 inches and a
variance of 1.64 square inches. If the heights of
the
male and female students are independent,
(A) 0.12 inches
what
is the standard deviation of the difference in
(B) 0.35 inches
their
(C) 1.48 heights?
inches
(D) 1.78 inches
(E) 2.24 inches
In a random survey of 500 women, 315 said they would rather be
poor and thin than rich and fat; in a random survey of 400 men,
220 said they would rather be poor and thin than rich and fat. Is
there sufficient evidence to show that the proportion of women who
would rather be poor and thin than rich and fat is greater then the
proportion of men who would rather be poor and then than rich and
fat?
(A) Because .63 > .55 there is strong evidence that the proportion of women is greater than
that of men.
(B) Because .0075 < 0.01 there is strong evidence that the proportion of women is greater
than that of men.
(C) Because 0.01<0.0329<0.05 there is strong evidence that the proportion of women is
greater than that of men.
(D) There is insufficient evidence that the proportion of women is greater than that of men.
(E) There is insufficient information to determine whether the proportion of women is
greater than that of men.
Suppose the correlation between two variables is
𝑟 = .28. What will the new correlation be if .17 is
added to all values of the x-variable, every value of
the y-variable is doubled, and the two variables are
interchanged?
(A) 0.28
(B) 0.45
(C) 0.56
(D) 0.90
(E) -0.28
Which of the following statements about
the correlation coefficient r is incorrect?
(A) It is not affected by changes in the measurement units of the variable.
(B) It is not affected by which variable is called x and which variable is called y.
(C) It is not affected by extreme values.
(D) It gives information about a linear relationship, not about causation.
(E) It always takes values between -1 and 1, even is the association is nonlinear.
Should there be more restrictions on handguns? In a
1995 pre-Columbine survey, 255 out of 1,020 adults
answered in the affirmative; in a 2000 post-Columbine
survey, 352 out of 1,100 answered affirmatively.
Establish a 90 percent confidence interval estimate of
the
difference
between
proportions
if
adults
in
1995
.25 (.75)
.32 the
.68)
(A) (.25 − .32) ± 1.645 1,020 + 1,100
and 2000 who support
more restrictions on handguns.
.25 (.75)
.32 .68)
(B) (.25 − .32) ± 1.645
1,020
+
1,100
(C) (.25 − .32) ± 1.96
.25 (.75)
.32 .68)
+
1,020
1,100
(D) (.25 − .32) ± 1.96
.25 (.75)
.32 .68)
+
1,020
1,100
(E) (.25 − .32) ± 2.576
.25 (.75)
1,020
+
.32 (.68)
1,100
One of the most bothersome side effect of antihistamines
is drowsiness. In an experiment, two antihistamines,
cetirizine and loratadine, are tested on three age classes:
12-19, 20-59, and 60-80. In each age class, the
participants are randomly assigned into two groups, with
one group receiving one drung, and the other group
receiving the other drug. Drowsiness level is compared
between
the
(A) Blocking on
age two
class groups for each age class. Which of the
following
describes the design of this experiment?
(B) Blocking onbest
antihistamine
(C) Matched pairs (cetirizine versus loratadine)
(D) Two factors (age class and antihistamine)
(E) Completely randomized
Twenty men and 20 women with migraine headaches
were subjects in an experiment to determine the
effectiveness of a new pain medication. Ten of the 20
men and 10 of the 20 women were chosen at random to
receive the new drug. The remaining 10 men and 10
women received a placebo. The decrease in pain was
(A)
Completely randomized
on factor, gender
measured
for eachwithsubject.
The design of this
(B)
Completely randomized
with on factor, drug
experiment
is
(C) Randomized block, blocked by drug and gender
(D) Randomized block, blocked by gender
(E) Randomized block, blocked by drug
The relation between the selling price of a car (in
$1,000) and its age (in years) is estimated from a
random sample of cars of a specific model. The
relationship is given by the following formula:
Which of the following can be concluded from this equation?
𝑆𝑒𝑙𝑙𝑖𝑛𝑔𝑃𝑟𝑖𝑐𝑒 = 24.2 − (1.182)𝐴𝑔𝑒
(A) For every year the car gets older, the selling price drops by approximately $2420.
(B) For every year the car gets older, the selling price goes down by approximately 11.82
percent.
(C) On average, a new car costs about $11,820.
(D) On average, a new car costs about $23,018.
(E) For every year the car gets older, the selling price drops by approximately $1182.
Data on the number of cancer deaths among
Americans (in 1,000s) and years (since 2001) result in
the regression line: 𝐷𝑒𝑎𝑡ℎ𝑠 = 550 − 6.05(𝑌𝑒𝑎𝑟𝑠) with
𝑟 = 0.863. What is the correct interpretation of the
(A) slope?
The number of cancer deaths among Americans has been dropping by an average of
6,050 per year since 2001.
(B) The baseline umber of cancer deaths among Americans is 550,000.
(C) The regression line explains 74.5 percent of the variation in cancer deaths among
Americans over the years since 2001.
(D) The regression line explains 86.3 percent of the variation in cancer deaths among
Americans over the years since 2001.
(E) Cancer will be cured in the year 2092.
Suppose we have a binomial random variable
where the probability of exactly four
𝑛 4
7
successes is
𝑝 (.37) . What is the mean
4
of the distribution?
(A) 2.52
(B) 2.59
(C) 4.07
(D) 4.41
(E) 6.93
A mortgage company advertises that 85 percent
of applications are approved. In a random
sample of 30 applications, what is the expected
number that will be turned down?
(A) 30 .85
(B) 30(.15)
(C) 30 .85 . 15)
(D) 30 .85 (.15)
(E)
.85 (.15)
30
A person has a 10 percent chance of winning the daily
office lottery. What is the probability she first wins on
the fourth day?
4
.10 3 (.90)
1
4
(B)
(.10) .90 3
3
(C) .10 3 (.90)
(A)
(D) (.10) .90
3
(E) None of the above gives the correct probability.
Suppose that 30 percent of the subscribers to a cable television
service watch the shopping channel at least once a week. You
are to design a simulation to estimate the probability that none of
five randomly selected subscribers watches the shopping channel
at least once a week. Which of the following assignments of the
digits 0 through 9 would be appropriate for modeling an individual
subscriber’s behavior in this simulation?
(A) Assign “0,1,2 as watching the shopping channel at least once a week and “3,4,5,6,7,8, and
9” as not watching.
(B) Assign “0,1,2,3” as watching the shopping channel at least once a week and “4,5,6,7,8 and
9” as not watching
(C) Assign “1,2,3,4,5” as watching the shopping channel at least once a week and “6,7,8,9, and
0” as not watching.
(D) Assign “0” as watching the shopping channel at least once a week and “1,2,3,4, and 5” as
not watching; ignore digits “6,7,8, and 9”.
(E) Assign “3” as watching the shopping channel at least once a week and “0,1,2,4,5,6,7,8, and
9” as not watching.
In a comparison of the life expectancies of two models of
washing machines, the average years before breakdown
in an SRS of 10 machines of one model, which is
compared with that of 15 machines if a second model.
The 95% confidence interval estimate of the difference is
(6,12). Which of the following is the most reasonable
conclusion?
(A) The mean life expectancy of one model is twice that of the other.
(B) The mean life expectancy of one model is 6 years while the mean life expectancy of the
other is 12 year.
(C) The probability the life expectancies are different is .95.
(D) The probability the difference in life expectancies is greater than 6 years is .95
(E) We should be 95 percent confident that the differences in life expectancies is between
6 and 12 years.
To determine the average spent on entertainment during
a year in college, a simple random sample of 35 students
is interviewed, showing a mean of $825 with a standard
deviation of $240. Which of the following is the best
interpretation of a 90 percent confidence interval
estimate for the average spent on entertainment during a
year in college?
(A) 90 percent of college students spend between $756 and $894 on entertainment yearly.
(B) 90 percent of college students spend a mean dollar amount on entertainment yearly that is
between $756 and $894.
(C) We are 90 percent confident that college students spend between $756 and $894 on
entertainment yearly
(D) We are 90 percent confident that college students spend a mean dollar amount between
$756 and $894 on entertainment yearly.
(E) We are 90 percent confident that the chosen sample, the mean dollar amount spent on
entertainment yearly by college students is between $756 and $894.
Suppose (48, 65) is a 95 percent confidence
interval estimate for a population mean 𝜇. Which
of the following is a true statement?
(A) There is a .95 probability that 𝜇 is between 48 and 65.
(B) If 100 random samples of the given size are picked and a 95 percent confidence
interval estimate is calculated from each, then 𝜇 will be in 95 of the resulting intervals.
(C) If 95 percent confidence intervals are calculated from all possible samples of the given
size, 𝜇 will be in 95 percent of those intervals.
(D) The probability that 𝜇 is in any particular confidence interval can be any value between
0 and 1.
(E) Confidence level cannot be interpreted until after data is obtained.
A police department public relations spokesperson
claims that the mean response time to a 911 call is 9
minutes. A newspaper reporter suspects that the
response time is actually longer and runs a test by
examining the records of a random sample of 64 such
calls. What conclusion is reached if the sample mean is
9.55 minutes with a standard deviation of 3.00 minutes?
(A) The P-value is less than .001, indicating very strong evidence against the 9-minute
claim
(B) The P-value is 0.01, indicating strong evidence against the 9-minute claim.
(C) The P-value is 0.07, indicating some evidence against the 9-minute claim.
(D) The P-value is .18, indicating very little evidence against the 9-minute claim.
(E) The P-value is .43, indicating no evidence against the 9-minute claim.