The manufacturer of a particular brand of tires claims they average at least 50,000 miles before needing to be replaced. From past studies of this tire, it is known that the life-span of these tires is normally distributed and that the population standard deviation is 8,000 miles. Research on 27 such tires resulted in the findings that the mean lifespan was 47000 miles. Using a significance level of 5%, does this mean that the tires average fewer than 50000 miles before needing to be replaced (and thus that the manufacturer's statement is wrong)? We should use a z test or t test? What are the correct hypotheses? H0: HA: Based on the hypotheses, find the following: Test Statistic = p-value = The correct decision is to: The correct conclusion is:
The manufacturer of a particular brand of tires claims they average at least 50,000 miles before needing to be replaced. From past studies of this tire, it is known that the life-span of these tires is normally distributed and that the population standard deviation is 8,000 miles.
Research on 27 such tires resulted in the findings that the mean lifespan was 47000 miles. Using a significance level of 5%, does this mean that the tires average fewer than 50000 miles before needing to be replaced (and thus that the manufacturer's statement is wrong)?
We should use a z test or t test?
What are the correct hypotheses?
H0:
HA:
Based on the hypotheses, find the following:
Test Statistic =
p-value =
The correct decision is to:
The correct conclusion is:
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