MATLAB: An Introduction with Applications
6th Edition
ISBN: 9781119256830
Author: Amos Gilat
Publisher: John Wiley & Sons Inc
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DATAfile: Costco
You may need to use the appropriate technology to answer this question.
Consumer Reports uses a 100-point customer satisfaction score to rate the nation's major chain stores. Assume that from past experience with the satisfaction rating score, a population standard deviation of
? = 13
is expected. In 2012, Costco, with its 432 warehouses in 40 states, was the only chain store to earn an outstanding rating for overall quality. A sample of 15 Costco customer satisfaction scores follows.95 | 90 | 83 | 75 | 95 |
98 | 80 | 83 | 82 | 93 |
86 | 80 | 94 | 64 | 62 |
(a)
What is the sample mean customer satisfaction score for Costco?
(b)
What is the sample variance? (Round your answer to two decimal places.)
(c)
What is the sample standard deviation? (Round your answer to two decimal places.)
(d)
Construct a hypothesis test to determine whether the population standard deviation of
? = 13
should be rejected for Costco. With a 0.05 level of significance, what is your conclusion?State the null and alternative hypotheses.
H0: ?2 ≤ 169
Ha: ?2 > 169
H0: ?2 < 169
Ha: ?2 ≥ 169
H0: ?2 ≥ 169
Ha: ?2 < 169
H0: ?2 = 169
Ha: ?2 ≠ 169
H0: ?2 > 169
Ha: ?2 ≤ 169
Find the value of the test statistic. (Round your answer to three decimal places.)
Find the p-value. (Round your answer to four decimal places.)
p-value =
State your conclusion.
Do not reject H0. We cannot conclude that the population standard deviation is not 13.Reject H0. We cannot conclude that the population standard deviation is not 13. Do not reject H0. We can conclude that the population standard deviation is not 13.Reject H0. We can conclude that the population standard deviation is not 13.
I only need help finding the P value.
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