A Physics professor is used to having a standard deviation of about 10 in his class grades. He feels that his current gr

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A Physics professor is used to having a standard deviation of
about 10 in his class grades. He feels that his current group of
students is different. He examines a random sample of 15 midterm
grades and found the standard deviation to be 13.6. Use both a
confidence interval and a hypothesis test at the 0.02 level of
significance to test if the standard deviation differs from 10.
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