cyclonefb3

04-08-2008, 10:10 PM

An actor claims he signs 90% of autographs asked for. A sample of 100 fans is taken with a normal distribution. What is the probability that the actor will give more than 90% of them autographs.

mean = 60

SD = 30

n=100

So I did this:

z = estimate - hypothesis 90 - 0

-------------------- --------- = 3

SD of estimate 30

z = 3

When you look on a normal table the z value at 3 = .9987

Does that mean there is 99% probability of this happening or am I doing this wrong?

mean = 60

SD = 30

n=100

So I did this:

z = estimate - hypothesis 90 - 0

-------------------- --------- = 3

SD of estimate 30

z = 3

When you look on a normal table the z value at 3 = .9987

Does that mean there is 99% probability of this happening or am I doing this wrong?