Recently,a university surveyed recent graduates of the English Department for their starting salaries.Four hundred graduates returned the survey.The average salary was $25,000 with a standard deviation of $2,500.What is the 95% confidence interval for the mean salary of all graduates from the English Department?
A)[$22,500,$27,500]
B)[$24,755,$25,245]
C)[$24,988,$25,012]
D)[$24,600,$25,600]

Question

Quizplus · Accepted Answer

The 95% confidence interval is calculated using the formula: mean ± (Z * (standard deviation/√n)). Here, Z is approximately 1.96 for 95% confidence, the mean is $25,000, the standard deviation is $2,500, and n is 400. This results in the interval [$24,755, $25,245].

Recently,a University Surveyed Recent Graduates of the English Department for Their