00:01
All right, so in this problem we are given a situation where a tire manufacturer has a 60 ,000 mile warranty for the tire tread and it says, you know, we consider the quality to be acceptable if less than five percent are worn out at 60 ,000 miles.
00:15
We test 250 tires and we find that 3 .6 % of them are worn out.
00:21
And we are interested in testing whether the two, you know, two hypotheses, basically the proportion of tires that are worn out after 60 ,000 miles is equal to 0 .05 and the proportion of tires that are worn out after 60 ,000 miles is less than 0 .05.
00:36
So, you know, the normal way that we do these sorts of, well, i see one is the first one is our hypothesis, then we have the alternative.
00:47
So in order to assess the evidence, what we are interested in doing is assuming our null hypothesis and computing the probability that we can write, that we observe an outcome that is at least as extreme as the outcome that we observed, right? so in our case, we want to look at the probability that we observe what we actually had, which is that in a sample of 250, we would get an outcome that is less than 3 .6%.
01:18
So, you know, that's pretty straightforward.
01:22
There's nothing pretty crazy here...