00:01
So we'll be assuming that that proportion is 15 % receive a ticket within five years, and we're looking at a sample size of 150 people being taken.
00:11
And we want to look at the sampling distribution of p bars, and the mean of the p bars would be centered at 0 .15.
00:20
The standard error or the standard deviation would be the square root of 0 .15 times 0 .85, divided by that sample size and let me quick get that for you square root of 0 .15 divided by 150 comes out to be almost 3 percent, 02915.
00:41
But i'm just going to store that in my calculator as x.
00:46
And n times p and n times 1 minus p are both greater than are equal to 5.
00:53
So this distribution would be approximately normal.
00:58
So we could kind of draw a little sampling distribution here, 0 .15 in the center, roughly 3%.
01:04
So if you go up to 0 .18 down to 0 .12, that's about one standard deviation away.
01:13
Now part b, we want to find what is the likelihood of having the proportion, the sample proportion, be within 3%.
01:22
So that's going to be about 68%, but not quite...