Question

Using the data in the Excel file Cell Phone Survey, determine if the mean response for Customer Service rating is different for the carriers (consider only AT&T, Verizon, and Sprint) for significance level of 5%.

Gender   Carrier   Type   Usage   Signal strength   Value for the Dollar   Customer Service
M   AT&T   Smart   High   5   4   4
M   AT&T   Smart   High   5   4   2
M   AT&T   Smart   Average   4   4   4
M   AT&T   Smart   Very high   2   3   3
M   AT&T   Smart   Very high   5   5   2
M   AT&T   Smart   Very high   4   3   5
M   AT&T   Smart   Very high   3   4   4
F   AT&T   Smart   Very high   3   2   3
F   AT&T   Smart   Very high   4   3   4
M   AT&T   Smart   Very high   3   3   1
M   Other   Smart   Average   1   2   4
M   Sprint   Smart   Very high   3   5   4
M   Sprint   Smart   Very high   3   5   3
F   Sprint   Smart   Average   2   5   4
F   Sprint   Smart   Average   3   5   4
M   Verizon   Smart   Average   4   3   3
F   Verizon   Smart   Very high   4   3   2
M   Verizon   Smart   Very high   5   5   5
F   Verizon   Smart   Average   3   3   3
M   Verizon   Smart   Very high   4   4   2
F   Verizon   Smart   Very high   4   5   3
M   AT&T   Camera   Average   5   4   5
M   AT&T   Camera   Very high   2   1   3
M   AT&T   Camera   Average   2   4   3
F   AT&T   Camera   Very high   3   3   3
M   AT&T   Camera   Average   5   5   3
F   AT&T   Camera   Average   4   3   3
M   AT&T   Camera   Average   4   2   4
F   AT&T   Camera   Very high   2   4   1
F   AT&T   Camera   Average   2   4   3
M   AT&T   Camera   Average   3   3   4
F   AT&T   Camera   Very high   3   2   3
M   AT&T   Camera   Very high   4   3   3
F   AT&T   Camera   Low   4   2   3
M   Other   Camera   Average   3   3   3
F   Other   Camera   Average   2   3   3
M   Other   Camera   Average   4   3   4
M   Sprint   Camera   Average   3   4   4
F   Verizon   Camera   Very high   3   4   3
F   Verizon   Camera   Very high   4   3   1
M   AT&T   Basic   Average   3   3   3
M   AT&T   Basic   Average   3   3   2
M   AT&T   Basic   Low   3   3   3
M   Other   Basic   Average   3   3   5
M   Other   Basic   Very high   4   3   3
M   Other   Basic   Very high   1   3   4
M   Other   Basic   Low   4   4   2
F   Other   Basic   Average   2   3   3
F   T-mobile   Basic   Low   3   4   4
M   T-mobile   Basic   Average   3   4   3
M   Verizon   Basic   Low   3   3   4
M   Verizon   Basic   Average   4   2   4

Answer 1

Result:

Using the data in the Excel file Cell Phone Survey, determine if the mean response for Customer Service rating is different for the carriers (consider only AT&T, Verizon, and Sprint) for significance level of 5%.

ANOVA is used to compare mean response for Customer Service ratings.

Ho: µ₁= µ₂= µ₃

H1: At least one of the mean is different from the others

Obtained F=1.19, P=0.3145 which is > 0.05 level of significance. Ho is not rejected. There is no sufficient evidence to conclude that mean response for Customer Service rating is different for the three carriers ( AT&T, Verizon, and Sprint).

Excel used for calculations:

One factor ANOVA
	Mean	n	Std. Dev
	3.1	26	0.99	AT&T
	3.0	10	1.15	Verizon
	3.8	5	0.45	Sprint
	3.2	41	1.00	Total
ANOVA table
Source	SS	df	MS	F	p-value
Treatment	2.35	2	1.176	1.19	.3145
Error	37.45	38	0.986
Total	39.80	40