00:01
Alright, so we're told for the scores on this exam, the population mean is 516 and it's normally distributed.
00:09
We gather a random sample of 2000 students and put them through a review class.
00:16
And their mean after the class comes out to be 521 with a standard deviation of 118.
00:27
So we're going to do a hypothesis test here.
00:31
A wants us to get the null and alternative hypothesis.
00:34
So the null hypothesis is just going to be that there's no change from the population.
00:39
So that's going to be that the mean is still equal to 516.
00:42
The alternative hypothesis is, well, we're hoping that the review class has made scores go up.
00:49
So it's going to be that the mean is greater than 516.
00:52
Okay, so that would be answer choice.
00:59
Let's see here.
01:08
Alright, so we're told for the scores on this exam, choice a.
01:13
B says that we're going to test this at an alpha of 0 .1.
01:20
Okay, we're going to see if it's statistically significant using the p -value approach.
01:26
So what we're going to do is find the test statistic.
01:29
So the test statistic is going to be the sample mean minus the population mean from my null hypothesis divided by s over the square root of n.
01:40
This you can do by hand.
01:44
There's also, if you're using like a ti calculator, you can also just calculate it with that...