00:01
Hi, i'm david and i'm here to hemmjohn.
00:03
Now let me bring up your question here.
00:06
In the question here, we are going to discuss about the competent interval for the mean.
00:12
The formula will be the x bar plus and minus the merging of the error, where the merging of the error is equal to the z and 4 over 2 times with the standard of the error and the standard of the error is equal to the sigma over score root the end.
00:27
In this question here, we are given the publishing standard division sigma equal to the 20.
00:35
We have the sample size n equals to the 64.
00:38
And we want to have the sample mean x bar equal to the 75 minutes.
00:45
And from here, the question asked 25 to find first of the phone will be the standard error.
00:51
And by the formula, it will equal to the sigma of square of n, equal to the 20 of square root, 64 equal to the 20 over 8 and it will equal to the 1st, the 1st, 2 equals to the 5 out of 2 equal to the 2 .5...