00:01
So we want to find the 99 % confidence interval for the difference between two proportions.
00:08
And our p hat 1 is 15 out of 60, which is 0 .25.
00:17
And our p hat 2, our estimate, is 0 .35, which was 35 out of 100.
00:26
And so let's go through and find that confidence interval.
00:29
We also have to list what the margin of error is and so on.
00:32
So we have the difference between our two proportions, which is 0 .25, less 0 .35.
00:39
So that estimated difference is negative 0 .1, plus or minus.
00:46
And then the z value that we're going to use is going to have 0 .005 in that upper tail.
00:53
And that's 2 .576.
00:55
And then we have to multiply that by that standard air.
00:58
And that standard air, we don't use pooled when we're finding a confidence in.
01:02
We'll take that 0 .25 times 0 .75 divided by the sample size of 60 plus the 0 .35 times its complement, 0 .65, divided by its sample size 100.
01:16
And now let's get this margin of air.
01:20
And so we'll put that into the calculator.
01:22
We have 2 .576 times the square root of, and we'll just type this in, 0 .25 times 0 .75, divided by 60 plus 0 .35 times 0 .65, divided by 100, and enter...