If X 127 sigma 24 and n 38 construct a 99 confidence int

If X = 127 , sigma = 24, and n = 38, construct a 99% confidence interval estimate of the population mean, mu.

Solution

CI = x ± t a/2 * (sd/ Sqrt(n))
Where,
x = Mean
sd = Standard Deviation
a = 1 - (Confidence Level/100)
ta/2 = t-table value
CI = Confidence Interval
Mean(x)=127
Standard deviation( sd )=24
Sample Size(n)=38
Confidence Interval = [ 127 ± t a/2 ( 24/ Sqrt ( 38) ) ]
= [ 127 - 2.715 * (3.893) , 127 + 2.715 * (3.893) ]
= [ 116.43,137.57 ]