Question

A very large study of college students’ study habits found that the time (in hours) that freshmen study each week is approximately normal with mean 24 hours and standard deviation 8 hours. What is the probability that a sample of size n equals 16 from this population would result in a sample mean greater than 30 hours? 0.7734 0.2266 0.0013 0.9987

Answer 1

Solution :

= / n = 8 / 16 = 2

P( 30) = 1 - P( 30)

= 1 - P[( - ) / (30 - 24) / 2]

= 1 - P(z 3)

= 0.0013