SOLUTION: In 2005, 74% of all airline flights were on-time. If we choose a simple random sample of 2000 flights, find the probability that (be as accurate as the proper process allows) (a)

Algebra ->  Probability-and-statistics -> SOLUTION: In 2005, 74% of all airline flights were on-time. If we choose a simple random sample of 2000 flights, find the probability that (be as accurate as the proper process allows) (a)       Log On


   

Question 1136238: In 2005, 74% of all airline flights were on-time. If we choose a simple random sample of 2000 flights, find the probability that (be as accurate as the proper process allows)
(a) at least 77% of the sample's flights were on time:

(b) at most 1420 of the sample's flights were on time:
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
z value is (0.77-0.74)/sqrt(0.74*0.26/2000)
z>3.06 p=0.0022
1420 is 0.71
this is the same probability
z<-3.06