Q 3.5

The following table shows the monthly unemployment rate in the United States from January 2011 until January 2013. These data can also be found in the Excel file titled US unemployment.xlsx.

9.1 9.0 8.9 9.0 9.0 9.1 9.0 9.0 9.0 8.9 8.6 8.5 8.3 8.3 8.2 8.1 8.2 8.2 8.2 8.1 7.8 7.9 7.8 7.8 7.9

Based on: http://www.bls.gov.

a. Calculate the mean. b. Calculate the median. c. Determine the mode. d. Describe the shape of this distribution.

Q 3.25

The following data represent the number of minutes customers at Wendy's had to wait in the drive-through line before their order was taken.

1 4 6 0 4 3 10 0 4

Calculate the z-scores for the following times: a. 1 minute b. 3 minutes c. 7 minutes d. 12 minutes

Q 3.31

Consider the following grouped sample data:

Values Frequency

10 to under 30 26

30 to under 50 35

50 to under 70 51

70 to under 90 33

a. Calculate the approximate mean of these sample data. b. Calculate the approximate standard deviation of these sample data.

Q 4.11

Use the following contingency table to answer the question below

Event A Event B

Event C 9 6

Event D 4 21

Event E 7 3

Determine the following probabilities:

a. P1A and C2

b. P1A and D2

c. P1B and E2

d. P1A and B2

Q 4.19

A local car dealership currently has 36 used GM, Ford, and Toyota vehicles on the lot that can be classified as either cars or trucks. The following data are available:

Twenty-six vehicles are cars.

Eleven vehicles are GMs.

Fifteen vehicles are Fords.

Three vehicles are both Toyotas and trucks.

Fourteen vehicles are both Fords and cars.

a. What is the probability that a randomly selected vehicle is a Toyota?

b. What is the probability that a randomly selected vehicle is a truck?

c. What is the probability that a randomly selected vehicle is a either a Ford or a car?

d. What is the probability that a randomly selected vehicle is a GM truck?

e. What is the probability that a randomly selected vehicle is a Toyota, given it is a car?

f. What is the probability that a randomly selected vehicle is a truck, given it is a Ford?

g. Construct a decision tree for these events