00:01
So now since the population variances are unknown, this will follow a t distribution.
00:07
So we have, so that will be for the party.
00:10
So the sample test statistics follows a t distribution because the population variances are unknown.
00:18
So when you come to the part b, okay, so it's actually part c, we have x1 bar is equal to 16, x2 is equal to 19, x bar 1 minus x bar 2 is equal to 16 minus 90 which is negative 3.
00:45
We have n1 to be 49, s 1 to be 5, n2 to be 64, and s 2 to be 6.
00:56
So our pool standard deviation will be a square root of n1 minus 1 times s1 squared plus n2 minus 1 times s1 squared plus n2 minus 1 times as 2 squared over n1 plus n 2 minus 2 so we get us to be the square root of 48 times 25 plus 60 times 36 over 49 plus 64 minus 2 and this give us a good standard deviation of 5 .8 5, 8, 9, 6...