00:01
We're told in a random sample of 100 people, 33 had kids.
00:06
And what we want to do is make a 90 % confidence interval, p, the population proportion of people who have kids.
00:20
And we're going to go ahead and assume that these 100 people are not connected in any way, right? there's, they're independent.
00:26
So it's not like two of them were, had a kid together, right? so just 100 people not connected in any way.
00:36
So our formula is going to be p hat plus minus z alpha over two times the square root p hat times one minus p hat all over n.
00:53
And the alpha is 0 .01 or 0 .10, excuse me.
01:00
And that's because of one minus the alpha gives us 0 .90 or that 90 % confidence.
01:06
So that's why it's 0 .10.
01:09
And our p hat value is x over n, the number of people that gets over the total number in our sample.
01:18
So it's 0 .33.
01:22
And the z score that corresponds with that 0 .10 over two alpha is 1 .645.
01:30
So we can already kind of make our confidence interval.
01:33
Not kind, we can.
01:34
0 .33 plus minus 1 .645 times the square root of 0 .33 times one minus 0 .33 all over, whoa.
01:52
I forgot the other three there...