00:01
Okay, so here we're going to be making two 90 % confidence intervals, but they're both for proportions, so it's going to be p -hat plus or minus z -star times the square root of p -hat times 1 minus p -hat over ed.
00:18
And the reason we're allowed to use this is because we have a large sample size on each of them, so this should work for us.
00:26
For both of them, the confidence level is 90%.
00:29
So the z star for that is 1 .645, which you can look up that critical value on a z table.
00:35
The p -hat for each of these is going to be different.
00:37
So for the first interval, the one with the male respondents, we had n -equals 435 and 18 % or p -hat of 0 .18, strongly agreed.
00:54
Okay, so it's going to be 0 .18.
00:56
Plus or minus 1 .645 times the square root of 0 .18 times 1 minus 0 .18 over 435.
01:09
So let's go ahead and compute that margin of vary really quick.
01:12
So that's 1 .645 times the square root of 0 .18 times 1 minus 0 .18 over 435.
01:21
And that gives us 0 .030 for our margin of error...