Recently, a university surveyed recent graduates of the English Department for their starting salaries. Four hundred graduates returned the survey. The average salary was $55,000. The population standard deviation is known to be $2,500. What is the 95% confidence interval for the mean salary of all graduates from the English Department?
A) 52,500, $57,500
B) 54,755, $55,245
C) 54,988, $55,012
D) 54,600, $55,600

Question

Quizplus · Accepted Answer

The 95% confidence interval is calculated using the formula: mean ± (Z * (σ/√n)). Here, the mean is $55,000, Z is 1.96 for 95% confidence, σ is $2,500, and n is 400. This results in the interval $54,755 to $55,245.

Recently, a University Surveyed Recent Graduates of the English Department