Question

A battery company claims that its batteries last an average of 100 hours under normal use. After several complaints that the batteries do not last this long, an independent testing laboratory decided to test the company’s claim with a random sample of 42 batteries. The data from the 42 batteries appeared to be unimodal and symmetric with a mean 97 hours and a standard deviation of 12 hours. Is this evidence that the company’s claim is false and these batteries actually last less than 100 hours?

Perform the test using a significance level of 0.10 (= 0.10).

What is the P-value and your decision for H 0

Answer 1

Hypothesis Test: Mean vs. Hypothesized Value
	100.00	hypothesized value
	97.00	mean 1
	12.00	std. dev.
	1.85	std. error
	42	n
	-1.62	z
	.0526	p-value (one-tailed, lower)
	93.95	confidence interval 90.% lower
	100.05	confidence interval 90.% upper
	3.05	margin of error

P value= 0.0526

Decision: Reject the null hypothesis, Ho

Since p value< alpha(0.10). We reject the null hypothesis. There is sufficient evidence to conclude that the company’s claim is false and these batteries actually last less than 100 hours.