00:01
So we have two samples here.
00:03
We're going to be doing a hypothesis test, and we're going to assume that those two populations are normal, approximately normal.
00:09
We're going to be doing a two -sample t -test.
00:12
And so first of all, we're going to write our ho and our ha.
00:15
And so we're going to start with our ho saying that the mean here, population one is equal to the mean, population two.
00:25
And they stated that they wanted population one to be the no ads.
00:29
So there we go.
00:30
And then our alternative is going to be that mu one is less than mu two, because we're trying to see if there's going to be less purchases on the no ad days.
00:41
To find the test statistic, here's the formula.
00:44
It's kind of complicated.
00:46
We're just going to plug in all the values that they give you, the mean one, standard deviation one, and the n1, population size.
00:52
And you're going to plug it into this big t formula, which i did here.
00:57
And so the first mean is 23 .9, and then 24 .7.
01:01
We're saying minus zero because we're comparing two to see if there's any difference.
01:05
And then we have our standard deviation one, 1 .9 squared over the n13, and then 1 .6 squared over the six.
01:13
When you do all that arithmetic, you end up with a negative test statistic of negative 0 .95...