## Stats with Steve!

## Weekly AP Statistics Practice Questions

# Question 1)

A random sample of 23 lizards were collected, and the length of each was determined.

1) According to the boxplot below, what is the approximate Interquartile range of the lengths?

2) According to the boxplot below, what is the median of the lengths?

# Answers:

1) The IQR is about 1.5

2) The median of the lengths is 6

# Question 2)

The histogram below shows the number of minutes needed by 84 kids to complete a maze. Which of the following statements is correct?

A) The distribution appears to be normal.

B) The distribution appears to be uniform.

C) The distribution is skewed to the left.

D) The distribution is skewed to the right.

# Answers:

C: The distribution is skewed to the left.

# Question 3)

The histogram below displays the frequencies of test taking times, in minutes, for 184 middle school students.

Which of the following could be the median of the waiting times, in minutes?

A) 1

B) 2.5

C) 8

D) 13

E) 21

# Answers:

C:8

# Question 4)

A cell-phone company claims its new Brand A phone has a longer battery life than its competitor’s Brand B phone. Eleven phones of each brand are tested independently, and the hours of battery life are shown in the table below.

A statistician wants to determine which phone to buy, and the battery life is a very important factor. Assuming all assumptions are met, which test should he conduct to determine if Brand A phones actually have a longer battery life than Brand B phones.

A) A one-sided, paired t-test

B) A one-sided, two-sample t-test

C) A one-sided, two-sample z-test

D) A two-sided, two-sample t-test

E) A two-sided, two-sample z-test

# Answers:

B: A one sided, two-sample t-test

# Question 5)

A team has three players, player A, player B and player C. The probability of failure for each of the players in any one year is .1, .2, and .4, respectively. If any one of the players fails, the team loses. The players fail independently.

1) Shade the area of the Venn diagram representing the event that the team loses.

2) What is the probability of the team losing?

3) What is the probability that the team does not lose?

# Answers:

1)

2) .568

3) .432

# Question 6)

A researcher wanted to compare the tomato diameters at three different farms: A, B and C. The histograms of the data are shown below. Which histogram has the greatest standard deviation?

# Answers:

C

# Question 7)

A random sample of 250 customers of the store revealed that 100 are in favor of a certain pasta brand. A 95 percent confidence interval for the proportion of the customers of the store who are in favor of the pasta brand is

# Answers:

A

# Question 8)

The boxplots below summarize two sets of data. Which of the following must be true?

A) Boxplot 2 has a greater median than boxplot 1.

B) Boxplot 1 has a greater IQR than boxplot 2

C) Both A and B

D) None of the above

# Answers:

C

# Question 9)

A citizen of a town was interested in finding the cheapest candy prices at nearby convenience stores. On randomly selected days over a period of one month, he recorded the candy prices (in dollars) at four convenience stores in his town. The boxplots of gas prices are seen below.

Which is the correct order of the store's IQRs from smallest to largest?

a)Store 1, Store 3, Store 4, Store 2

b)Store 3, Store 1, Store 4, Store 2

c)Store 2, Store 4, Store 1, Store 3

d)Store 1, Store 4, Store 2, Store 3

# Answers:

B

# Question 10)

A random sample of 21 students in an 8th grade math class was collected. The Information obtained included the amount of time it took to complete the warm-up in the beginning of class. A histogram of the data is shown below.

Which of the following intervals includes the median?

A)0-2

B)2-4

C)4-6

D)6-8

E)This can not be determined

# Answers:

B