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

 

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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 139 with a standard deviation of 16.5865. The superintendant wants to know if the standard deviation has changed this year. Previously, the population standard deviation was 29. is there evidence that the standard deviation of test scores has decreased at the a- 0.025 level? Assume the population is normally distributed. 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 139 with a standard deviation of 16.5865. The superintendant wants to know if the standard deviation has changed this year. Previously, the population standard deviation was 29. is there evidence that the standard deviation of test scores has decreased at the a- 0.025 level? Assume the population is normally distributed.

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