00:01
Hi, i'm david and i'm here to have you answering your question.
00:04
Now let me bring up your question here.
00:06
In this question we will discuss about the 90 % comptial interval.
00:10
Recorder for the competal interval for the mean, it will be the xb plus or minus the z n5 out of 2 times the s divided by the square root of n.
00:30
And in this question we are given that the sample mean equal to the 30 and then we are given the sample variance equal to 86.
00:46
So therefore it has just that s equal to square of the 86 and then we do that we get equal to 9 .27 4 and we see we have sample of the 5 observation.
01:04
So this will be n equal to 5.
01:07
And because the symbol here is small and the population is not from the oh so we have it is normally distributed so therefore we can use the z here.
01:18
So we have the 90 % confident interval.
01:26
It means then the n -fah equal to 100 minus 90 % equal to 10 % therefore the n -file over 2 equal to 10 % the value 2 will be 5%.
01:39
So it means that unfa equal to 0 .05 and we need to look on the and 5 equal to 05 on the table.
01:48
So let me bring up the z table and so you have to look up the z and far over 2 now...