00:01
Okay, so we're told that x has mean 20 plus a and standard deviation 0 .5b plus 10.
00:15
Part a says to find your mu and sigma, but now mu just means mean and sigma just means standard deviation.
00:22
So unless there's more information in the question that we can't see, then your mean is just 20 plus a and your standard deviation is just 0 .5b plus 10.
00:30
For part b, it says x bar is a sample of 35 that fit this distribution x.
00:43
And it says, is it normally distributed? it is normally distributed by the central limit theorem because each element in the sample is randomly selected and we have a sample size.
01:04
They are independent as well.
01:06
And we have a sample size of bigger than or equal to 30.
01:10
So it is normally distributed.
01:12
Part c then says, what's the mean and standard deviation of x bar? well, the mean of x bar is just the same as the mean of x, so that's going to be 20 plus a.
01:23
And the standard deviation of x bar is the standard deviation of x over the square root of the sample size, which is 35...