Question

A magazine provided overall customer satisfaction scores for AT&T, Sprint, T-Mobile, and Verizon cell-phone services in major metropolitan areas throughout the United States. The rating for each service reflects the overall customer satisfaction considering a variety of factors such as cost, connectivity problems, dropped calls, static interference, and customer support. A satisfaction scale from 0 to 100 was used with 0 indicating completely dissatisfied and 100 indicating completely satisfied. The ratings for the four cell-phone services in 20 metropolitan areas are contained in the Excel Online file below. Construct a spreadsheet to answer the following questions.

City	AT&T	Sprint	T-Mobile	Verizon
Atlanta	69	68	74	80
Boston	68	66	77	77
Chicago	70	67	73	78
Dallas	74	67	77	79
Denver	70	69	76	78
Detroit	72	67	80	80
Jacksonville	72	66	78	82
Las Vegas	71	70	77	82
Los Angeles	65	67	71	79
Miami	67	71	76	81
Minneapolis	67	68	78	78
Philadelphia	71	68	74	79
Phoenix	67	68	79	82
San Antonio	74	67	78	81
San Diego	68	70	75	80
San Francisco	65	71	76	76
Seattle	67	69	77	78
St. Louis	73	68	77	80
Tampa	72	65	76	80
Washington	71	70	74	77

a. Consider T-Mobile first. What is the median rating (to 1 decimal)?

b. Develop a five-number summary for the T-Mobile service.

Smallest value
First quartile (to 2 decimals)
Median (to 1 decimal)
Third quartile (to 2 decimals)
Largest value

c. Are there outliers for T-Mobile?

_________Yes, the data contain outliersNo, the data do not contain outliers

d. Repeat parts (b) and (c) for the other three cell-phone services.

	AT&T	Sprint	Verizon
Smallest value
First quartile (to 2 decimals)
Median (to 1 decimal)
Third quartile (to 2 decimals)
Largest value

Are there outliers for AT&T?

_________Yes, the data contain outliersNo, the data do not contain outliers

Are there outliers for Sprint?

_________Yes, the data contain outliersNo, the data do not contain outliers

Are there outliers for Verizon?

_________Yes, the data contain outliersNo, the data do not contain outliers

e. Which of the following box plots accurately displays the data set?

#1	Rating	#2	Rating
#3	Rating	#4	Rating

_________Box plot #1Box plot #2Box plot #3Box plot #4

Which service did the magazine recommend as being best in terms of overall customer satisfaction?

_________AT&TSprintT-MobileVerizon

Answer 1

a) Median for T- Mobile = 0.5(n+1)th value =10.5th value of sorted data = 76.5

Minimum = 71

First quartile, Q1 = 0.25(n+1)th value =5.25th value of sorted data = 74.25

Median = 76.5

Third quartile, Q3 = 0.75(n+1)th value = 15.75th value of sorted data = 77.75

Maximum = 80

c) Are there outliers for T-Mobile?

No, the data do not contain outliers.

d)

	AT&T	Sprint	Verizon
Minimum =	65	65	76
First quartile, Q1 =	67	67	78
Median =	70	68	79.5
Third quartile, Q3 =	72	69.75	80.75
Maximum =	74	71	82

Are there outliers for AT&T?

No, the data do not contain outliers.

Are there outliers for Sprint?

No, the data do not contain outliers.

Are there outliers for Verizon?

No, the data do not contain outliers.

e. Which of the following box plots accurately displays the data set?

e) Boxplot:

The service magazine recommend as being best in terms of overall customer satisfaction:

Verizon