00:01
Okay, so the first thing we need to do for this problem is set up a null hypothesis.
00:08
So the null hypothesis would mean that there's basically it's not exciting.
00:13
So that basically so that whatever the tire company claims is true.
00:18
So we're going to assume that the mean is greater than or equal to the 50 ,000 mile mark.
00:28
Okay, so just assuming that the claim is true, which means the alternative hypothesis is the, that the mean is less than 50 ,000.
00:41
Okay.
00:43
So we know that the data should be normally distributed.
00:49
Let me write it the way the book writes it.
00:55
Okay, so we have the means should be normally distributed around 50 ,000 with the standard deviation.
01:08
In this case, it gave us to us as 8 ,000 was the population.
01:17
And we're testing 28 tires.
01:26
So about root 28.
01:30
Okay...