Mathematics, 05.05.2020 05:09 batmandillon21

In a school district, all sixth grade students take the same standardized test. The superintendant of the school district takes a random sample of 25 scores from all of the students who took the test. She sees that the mean score is 134 with a standard deviation of 6.0547. The superintendant wants to know if the standard deviation has changed this year. Previously, the population standard deviation was 13. Is there evidence that the standard deviation of test scores has decreased at the α=0.01 level? Assume the population is normally distributed.

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In a school district, all sixth grade students take the same standardized test. The superintendant o...