SOLUTION: In a study of the time college freshmen use to study each week, it is found that the mean is 6.8 hours with a standard deviation of 2.5 hours. If 100 freshmen are randomly select

Algebra ->  Probability-and-statistics -> SOLUTION: In a study of the time college freshmen use to study each week, it is found that the mean is 6.8 hours with a standard deviation of 2.5 hours. If 100 freshmen are randomly select      Log On


   

Question 437771: In a study of the time college freshmen use to study each week, it is found that the
mean is 6.8 hours with a standard deviation of 2.5 hours. If 100 freshmen are
randomly selected, what is the probability that their mean weekly study time
exceeds seven hours?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi

*Note: z+=%28X+-+mu%29%2F%28sigma%2Fsqrt%28n%29%29

In a study of the time college freshmen use to study each week,

mean is 6.8 hours with a standard deviation of 2.5 hours

Sample size n = 100 Find: P(X > 7hr)   

 z = (7-6.8)/(2.5/10) = .2/.25 = .8

P(z >.8) = 1 - .7881 = .2119