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There are 300 students enrolled in Business Statistics. Historically, test score

ID: 3232743 • Letter: T

Question

There are 300 students enrolled in Business Statistics. Historically, test scores are normally distributed with a standard deviation of 25.6. Your instructor randomly selected a sample of 45 examinations and finds a mean of 69.4. Determine a 90% confidence interval for the mean score for all students taking the course. (Round your answer(s) to 3 decimal places.)

90% CI = ______ to ______ ?   

There are 300 students enrolled in Business Statistics. Historically, test scores are normally distributed with a standard deviation of 25.6. Your instructor randomly selected a sample of 45 examinations and finds a mean of 69.4. Determine a 90% confidence interval for the mean score for all students taking the course. (Round your answer(s) to 3 decimal places.)

90% CI = ______ to ______ ?   

Explanation / Answer

The statistical software output for this problem is:

One sample Z confidence interval:
: Mean of population
Standard deviation = 25.6

90% confidence interval results:

Hence,

90% confidence interval will be:

63.123 to 75.677

Mean n Sample Mean Std. Err. L. Limit U. Limit 45 69.4 3.8162227 63.122872 75.677128