00:01
So this one's going to be a little longer.
00:02
We're normally distributed that i'm going to call it in d.
00:05
Don't forget z is your data item minus your mean divided by our standard deviation.
00:09
We're told the means 48, the standard deviation is 20, our sample size is 11.
00:16
Part a, x is approximately normal distributed with a mean of 48 and a standard deviation of 20.
00:24
Some books use the mean and the standard deviation.
00:28
Squared.
00:30
I'm assuming yours doesn't use that because i've seen both, but i'm assuming that it's just the standard deviation.
00:41
B, x bar is approximately normal.
00:45
The mean of the sampling distribution is the same as the mean, 48, but the standard deviation of the sampling distribution is the standard deviation divided by the square root of n or 20 divided by the square root of 11, which is 6 .03023.
01:07
So 48, 6 .03023.
01:11
And you can round where you need to round.
01:16
C, you want the sum of x that's approximately normally distributed? well, the mean is n times the mean of the sampling distribution for the mean...