00:01
So let us start with the concept which we are going to use here for this question.
00:06
So since we know that the confidence interval can be given by the formula, whatever will be the mean, let us say mu x bar plus minus of the z critical into standard deviation sigma by under root of n, where n is the sample size sigma standard deviation z critical means critical value of z.
00:28
So, according to question we have to compute the 99 % of confidence.
00:35
So, for 99 % of confidence significance level alpha should be equals to 1 minus of 99 % that means 0 .99 that will comes out equals to 0 .1.
00:48
Now, according to question at initial the random sample of 40 visitors that means sample size is given equals to 40.
00:57
So if you see that 93 .43 is basically remaining that the sample mean mu x bar is equals to 93 .43 here.
01:10
In similar way the standard deviation sigma that we have been given equals to 15.
01:16
So all the values is we have given here we just have to compute the confidence interval.
01:21
So first of all we going to need z critical that should be equal to z of alpha by 2.
01:29
So that should be equal to z of 0 .1 by 2 which will be equal to z of 0 .05...