00:01
All right, so we want to construct a 95 % confidence interval for the on -time performance of this american airlines flight from new york to l .a.
00:10
And we have a given data set of values, 12 values, and we calculate a mean and standard deviation for those values because that's what we need for the confidence interval.
00:20
So you can do this in a calculator, which i did.
00:22
You could also do them out by hand, which will take a lot longer.
00:25
So we get a mean of negative 9 .2, which means that they left.
00:30
Sooner than they should have.
00:31
And a standard deviation of 23 .9, and we have n is equal to 12.
00:37
So what we want to do now is to find our confidence interval.
00:41
We're going to take our mean, and we're going to add or subtract the t score associated with a 95 % confidence interval with that sample size of 12 times the standard deviation over square root of n.
00:56
So the first thing i want to do is find the t score...