00:01
So in this first time we are given, sample size 1 to be 79, sample size 2 to be 71, sigma 1 to be 11, sigma 2 to be 12.
00:22
So sample size, sample mean, this is a sample mean, so sample size is 1 to 1, and sample size 2 to be 30.
00:32
So you can find our standard error for the mean to be equal to the 2.
00:37
1 squared over and 1 plus sigma 2 squared over n 2 which gives us the root of 11 squared over 25 plus 12 squared over 30 which is 3 .104 835 so we get 3 .1.
01:07
So the point estimate of the difference between the two population mean will be mean 1 minus which will be x bar 1 minus x bar 2 so we get 79 minus 71 and this gives us 8 our critical value will be so the z critical will be z 1 minus 0 .95 on 2 which gives us 1 .96 so we can find our margin of error to be the z critical times the standard error which gives us 1 .96 times 3 .1.
02:02
And this gives us 6 .09, which is approximately, so 6 .090, which is approximately 6 .09.
02:18
So now we can find a 95 % confidence interval, which is x -bar 1 minus x bar 2 plus or minus, or z -critical.
02:32
Times the standard error.
02:35
So we had this to be 8 plus or minus.
02:40
So this gave us 6 .09.
02:43
So this gives us confidence interval of 1 .91 and 14 .09...