00:01
So we have a hypothesis test where the null is that sigma is equal to 4 .4.
00:07
The standard deviation is equal to 4 .4.
00:10
And then the alternative hypothesis is that it is not equal to 4 .4.
00:17
And we're told that the sample size is 19.
00:25
And we're also told that the population is normally distributed, which is nice.
00:30
And we're also told that the sample standard deviation, is 5 .2.
00:40
And we're going to do a little kye squared test to test for this hypothesis.
00:47
And that kai squared statistic is given as n minus 1 times the sample variance all over.
00:55
The value we're testing it against.
01:02
And we're also told that we're testing at the alpha of 0 .01.
01:10
Level of significance.
01:13
All right, so the first part, part a, asks us to get the test statistic.
01:19
So it's a matter of plugging our n, which is 19 minus 1 times 5 .2 squared all over 4 .4 squared, which is equal to 25 .14.
01:35
And then the p value using my spreadsheet, my google sheets.
01:48
And to do that, i use this function called chi -dist.
01:52
And in it, you put your kai squared statistic with the degrees of freedom.
01:59
And that's given as n minus 1.
02:02
So in this case, you put it in 25 .14, degrees of freedom of 18.
02:07
And the p value ends up being 0 .1211...