00:01
For this problem, we are told that essentially what matters.
00:04
We have two different samples, one female, one male, where we have n1 equals 50, or pardon me, i misread that, n1 equals 20.
00:13
Sample mean 1, so x bar 1, equals 50 .3.
00:19
Sample 1 standard deviation, so s1, is equal to 13 .215.
00:27
And then we have n2 equals 20.
00:31
X bar 2 equals 39 .8 and s2 equals 10 .04.
00:40
For part one, we're asked to write the null and alternative hypotheses.
00:45
So in this case, we would have that based on the context, we're told that they're just trying to, yeah, okay, they're trying to test to determine if the mean age of all female purchasers exceeds the mean age of all male purchasers.
00:59
So our null hypothesis here is that mu 1, minus mu2 equals 0, and then our alternate hypothesis, since mu 1 is the mean age for females, the alternate hypothesis is going to be that mu 1 minus mu 2 is greater than 0.
01:18
For part 2, we're asked for the degrees of freedom.
01:22
Well, in this case, the degrees of freedom will be n1 plus n2 minus 2.
01:27
So that's 20 plus 20 or 40 minus 2, which gives us a result of 38.
01:33
Then we're asked for the t critical value.
01:38
So we can use either technology or a relevant table here, but i like to use this website stat key.
01:45
We can go to theoretical distributions, 38 degrees of freedom, and this is going to be a right -tail test with a alpha value of 0 .05 to the right...