00:01
So the large school district held a track meet for all high school students, and the population of female students participating had a normal distribution.
00:16
So x for the females was normally distributed with a mean running time of 8 .8 and a standard deviation of 3 .3.
00:34
The population of male students followed a normal distribution with mean for the males equal to, let's see here, 7 .3 minutes.
00:57
And the standard deviation for the males is 2 .9 minutes.
01:04
Then we have n female equal 8 and n male equal 8.
01:11
We have samples of 8 from each.
01:17
And x bar f represents the sample mean running time for the females.
01:25
Females and x bar m represents the sample mean running time for the males.
01:31
Then find and interpret the mean as a deviation for the sampling distribution of the difference in sample means.
01:40
Well, x bar minus x bar f minus x bar m is going to be also normal, and it's going to have a mean for the difference equal to the mean from the females minus the mean from the males, and that is going to be 8 .8 minus 7 .3, so that is 1 .5.
02:19
The standard deviation for the difference between the males and the females is going to be the square root of sf squared over nf plus s squared for the mils over the number of mils.
02:41
So that is going to be 3 .3 squared over 8 plus 2 .9 squared over 8...