00:01
So we have a sample size of 100, and the true proportion is 0 .4.
00:06
And we want to find what the expected value is for this proportion, and that is just 0 .4.
00:14
And then we want to determine what the standard error is, and that is the standard deviation of these p -hats.
00:23
Sometimes they're called, they have a hat on top of them in some textbooks as opposed to a bar above it.
00:29
And that is the square root of, and we take 0 .4 times 0 .6 divided by 100.
00:38
So this is going to end up being, let's see, 0 .4 times 0 .6 underneath the radical divided by 100.
00:47
This comes out to be approximately 0 .490.
00:53
And part c asks you to describe the sampling distribution.
01:00
And the sampling distribution, well, if n times p and n times 1 minus p, and this calculation would be 100 times 0 .4, which would be 40, and this would be 100 times 0 .6, which would be 60...