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In: Statistics and Probability

Grades on a standardized test are known to have a mean of 940 for students in...

Grades on a standardized test are known to have a mean of 940 for students in the United States. The test is administered to 436 randomly selected students in​ Florida; in this​ sample, the mean is 952.22 and the standard deviation ​(s​) is 101.52.

a) The​ 95% confidence interval for the average test score for Florida students is ​( 942.67​, 961.77​). ​(Round your responses to two decimal places.​)

b) Is there statistically significant evidence that Florida students perform differently than other students in the United​ States?

The​ 95% confidence interval for the average test score for Florida students does not include mu ​= 940​, so the null hypothesis that mu ​= 940 ​(that Florida students have the same average performance as other students in the United​ States) can be rejected at the​ 5% level.

c) Another 486 students are selected at random from Florida. They are given a​ 3-hour preparation course before the test is administered. Their average test score is 957.86 with a standard deviation of 89.30. The​ 95% confidence interval for the change in average test score associated with the prep course is ​( nothing​, nothing​). ​(Round your responses to two decimal places.​)

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orchestra answered 1 year ago
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