00:01
Jasmine, it looks like you have nine people and they have done a matched pair study, a before and after.
00:10
And so if we let the number of headaches be the after minus the before, this is some type of relaxation training, it looks like the mean of the differences is negative three and that the standard deviation of the differences is three.
00:33
And then you want to see, does the training significantly reduce the number of headaches? so we would be assuming that the mean difference is zero so that it doesn't have any impact.
00:47
And alternately, that the mean difference is negative, meaning that it does reduce down you have more of these migraines before than after, or headaches, i should say.
00:58
And so this is, we would assume that these are simple random sample and that the population is approximately normal because otherwise this is a very small sample size and we will be performing a t -test.
01:13
And so our t -test, our test statistic will be a t value with eight degrees of freedom and we'll take that negative three minus zero and then we'll take the standard deviation divided by the square root of the sample size.
01:30
And so that gives us, we know that that's three and three over three is one, so we're going to have a test statistic of negative three.
01:38
And we can either do this, you don't have a significance level, but let's just find what the p value is.
01:44
So the likelihood of getting a t value with eight degrees of freedom less than or equal to negative three since we're doing a one -tailed test, a left -tailed test...