Question

How does cellphone service compare between different cities? The data stored in CellService represent the rating of Verizon and AT&T in 22 different cities. (Data extracted from "Best Phones and Service," Consumer Reports, January 2012, p. 28, 37.) At the 0.05 level of significance, is there evidence of a difference in the mean cellphone service rating between Verizon and AT&T? You need to download "CellService” data file. End of document

Answer 1

The hypothesis being tested is:

H₀: µ₁ = µ₂

H₁: µ₁ ≠ µ₂

The output is:

Verizon	AT&T
73.00	60.14	mean
1.88	3.67	std. dev.
22	22	n
	42	df
	12.864	difference (Verizon - AT&T)
	8.490	pooled variance
	2.914	pooled std. dev.
	0.879	standard error of difference
	0	hypothesized difference
	14.642	t
	4.23E-18	p-value (two-tailed)

Since the p-value (0.0000) is less than the significance level (0.05), we can reject the null hypothesis.

Therefore, we can conclude that there is a difference in the mean cellphone rating between Verizon and AT&T.

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