00:01
Hello, so here we're given that n is equal to 60.
00:02
Sample mean x bar is 52 .5, and the population's standard deviation sigma is equal to 8.
00:08
So here our hypotheses are h -not is that mu is less than equal to 50, and our alternative hypothesis is that mu is greater than 50.
00:17
So we get our test statistic here as x bar minus mu not, that's 52 .5 minus 50, and then divided by 8 divided by the square root of 60, which is going to be equal to 2 .42.
00:36
So for an upper tail test, the critical value here of the test statistic corresponds to an area of alpha being 0 .05 in the upper tail, so we can use the standard normal probability table to find that z equals 1 .645 provides an area of 0 .05 in the upper tail.
00:56
So the critical value rejection rule here for our significance of 0 .05 is to reject h0 if z is greater than 1 .645.
01:12
Well, here we have that 2 .42 is greater than 1 .645.
01:16
So therefore, we reject the null hypothesis at a 0 .05 level of significance.
01:25
And then for part b, we're given the sample here is 60.
01:30
Sample mean is 51.
01:31
Again, the standard deviation is 8...