00:01
So we're starting out with the null hypothesis that the mean is equal to 100, and alternately a one -tail test that it is greater than 100.
00:12
And we have a sample size of 100, and the mean being 106 with a sample standard deviation of 35.
00:22
And we had to find the t value.
00:24
And the t value with technically 99 degrees of freedom is 106 minus 1 .5.
00:30
100 divided by 35 divided by the square root of 100 or divided by 10.
00:37
And that test statistic comes out to be 1 .714.
00:44
And using software to find that p value using the tcdf, we find that that p value comes out to be 0 .04.
00:55
48 and i believe that your significance level was given to be 1%.
01:03
And so since that is higher than 1%, we would fail to reject the null.
01:16
So we would not have evidence to say that the mean is higher than 100.
01:21
And then in part b, we were to change the standard deviation to 25.
01:30
So reduce the standard deviation.
01:33
And in so doing, we can see that our test statistic would end up being that 106 minus 100 divided by 25, divided by the square root of 100 or divided by 10.
01:47
And now our test statistic comes out to be a value of 2 .4, and then the likelihood of having that...