00:01
Hello, students, we are going to write here, we are given x bar value as 49 .78 and sigma value which is 6 .4 sample size is given.
00:10
We are going to construct 90 % confidence interval for mu.
00:14
And in the second case, we are going to write here if the population were not approximately normal, would the confidence interval constructed in part a, b, valid.
00:25
So we are going to write here in the first.
00:30
Case, our confidence interval can be calculated as if i write here this is sample mean plus minus margin of error.
00:44
So this will come out as if i write here, sample mean value is 49 .78 plus margin of error so x x xlpha y2 multiplied by sigma divided by under root of n that is equivalent to 49 .78 plus minus.
01:08
So z alpha y2 is so at 90 % confidence interval, z alpha y2 value will be if i write here for this, this is 1 .645 multiplied by sigma.
01:21
Sigma is 6 .4 divided by n so n value is under root of 7 8 if i write here so this will be calculated as so this will be 49 .78 plus minus if i calculate this this value will come out as 10 .5 to 8 that must be divided by if i write here 10 .5 to 8 .5 to 8...