A graduate picks 25 exams at random from a total of 194 exams. Those 25 exams...

A graduate picks 25 exams at random from a total of 194 exams. Those 25 exams have a mean of 78.2% ± 17.1% (mean ± 1 standard deviation). You may assume that these 25 exam scores are approximately normally distributed.

a) Estimate the population mean exam score and its confidence interval for the 95% confidence level.

b) Estimate the population exam score standard deviation and its confidence interval for the 95% confidence level.

c) Estimate how many students failed the exam if the passing grade is 60%.

d) Estimate how many students scored above 90% on the exam.

e) The graduate draws another set of exams of 25 exams, and these exam scores are not normally distributed: they are skewed towards a high score. What would you tell the graduate so that s/he can estimate the population mean using methods we learned in class?

Expert Solution

milcah answered 1 year ago

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