00:02
We're given an 80 % confidence interval from 0 .27 to 0 .45.
00:07
And our first asks for the sample proportion, or the p -hap, which is going to be the exact middle of this confidence interval.
00:15
So to find the exact middle, we can do 0 .27 plus 0 .45 and divide by 2.
00:21
And that'll give us our sample proportion.
00:24
And that works out to be 0 .36 is the sample proportion.
00:30
And then for our margin of error, that's going to be the distance.
00:34
0 .36 is from the end of our confidence interval.
00:40
So i'm going to do 0 .45, take away 0 .36 gives me a margin of error of 0 .09.
00:49
And then part c, what is the critical value? at 80 % confidence, the critical value is 1 .282.
00:59
And then part d for our standard error, we can find that by saying our margin of error is equal to our critical value times the standard error.
01:15
I'll use se for standard error...