Question 1

A department store manager is interested in the number of complaints received by the customer service department about the quality of electrical products sold by the store. Records over a 5-week period show the following number of complaints received each week:
13 15 8 16 8

a. Compute the mean number of weekly complaints.

b. Calculate the median number of weekly complaints.

c. Find the mode.

Question 2

The demand for bottled water increases during the hurricane season in Florida. A random sample of 7 hours showed that the following numbers of 1-gallon bottles were sold in one store:

40 55 62 43 50 60 65

a. Describe the central tendency of the data.

b. Comment on the symmetry or skewness.

Question 3

Compute the variance and standard deviation of the following sample data:

6 8 7 10 3 5 9 8

Question 4

The following is a random sample of five (x, y) pairs of data points:

(12, 200) (30, 600) (15, 270) (24, 500) (14, 210)

2

a. Compute the covariance.

b. Compute the correlation coefficient.

Question 5

A major airport recently hired consultant John Cadariu to study the problem of air traffic delays. He recorded the number of minutes planes were late for a sample of flights in the following table:

Minutes late

0 < 10
10 < 20
20 < 30
30 < 40
40 < 50
50 < 60

Number of flights

30
25
13
6
5
4

a. Calculate the mean number of minutes late.

b. Compute the sample variance and standard deviation.