00:01
In our first problem, in a test of computer components, it is found that the mean time between failures is 520.
00:12
This is going to be our null hypothesis.
00:14
We're going to be testing to see if that has increased.
00:19
We have a sample of 10.
00:21
We have a sample mean of 537 .1 and a sample standard deviation of 20 .7.
00:28
We're going to test at a 0 .05 level of significance.
00:31
This is going to be a t -test, so t will be 537 .1 minus 520 divided by 20 .7 divided by the square root of 10.
00:41
That gives us a test statistic of 2 .6123, which has a corresponding p -value of 0 .0141, which is less than alpha at 0 .05.
00:54
So we are going to reject the null hypothesis.
00:58
For part b, we're going to be finding a 92 % confidence interval...