00:01
Hi, i'm david and i'm here to have you answer your question.
00:03
Now let me bring up your question here.
00:06
In this question, when you discuss about the confidence interval for the mean, let me remind you that the confidence for the mean, we have the x bar plus or minus z and 4 over 2 times with the sigma over square of n.
00:25
Now in this question here we're given that the sum of n equal to the 60 and and we have the sample mean x bar equal to the 70 and the population standard division equal to the 15.
00:40
The question i is asking us to find the 95 % calm interval for the publication mean.
00:47
We see that we have obtained the x bar, sigma and n.
00:51
The only quantity we don't know will be the z and 4 over 2.
00:55
At the 95 % calm interval and 5 equal to the 5%.
00:59
Therefore, n4 over 2, it will equal to the 2 .5%, which is equal to 0 .0 .25.
01:08
It will look up the z table, the z of the zbunzel 25, equal to 1 .96.
01:14
Therefore, we have the 95 % compote interval.
01:18
It will be the x bar 70 plus and minus 1 .96...