00:03
So i know that the population has a probability of 0 .42.
00:07
I know my sample size is 400.
00:09
And i want to find the probability from those samples of size 400 of getting a probability of 0 .39 to 0 .45.
00:18
So in order to do that, i need to think about the normal distribution.
00:22
What i mean is 0 .42 .0 .39 is going to be over here.
00:26
And 0 .45 is going to be over here.
00:28
And this is the area i'm finding in here.
00:30
So what i need to find is my standard deviation.
00:33
So to calculate my senior deviation, i'm going to use the square of 0 .42 times 1 minus 0 .42 over n, which is my sample size.
00:41
And that gives me a standard deviation of 0 .247.
00:46
So now using normal cdf, my lower bound is 0 .39.
00:52
My upper bound is 0 .45...