00:01
Okay, the average age of bank managers is normally distributed, and the average age is 40, and the standard deviation is 5.
00:09
So the question is, find the probability that a randomly selected one is between 35 and 46.
00:16
So first of all, you need a normal curve table or a z table.
00:20
I just stole this one off the internet, so yours may be a little bit different.
00:26
Okay, and you need this formula, and it goes z.
00:29
Okay, this is the z table.
00:32
So we have to convert these into z numbers, x minus x bar over standard deviation.
00:44
Where x bar is the average, sd is the standard deviation, and x is the number that you want to know about.
00:51
So we have two numbers.
00:52
We have to find z values for 35 and 46.
00:56
So let's do 35 first...