Question

A random sample of n=12

values taken from a normally distributed population resulted in the sample values below. Use the sample information to construct an 80​% confidence interval estimate for the population mean.

106

101

95

95

107

108

113

110

105

110

101

100

The 80​% confidence interval is from ​$ to ​$

Answer 1

We have for given data,      
          
Sample mean =104.25  
Sample standard deviation =5.864
Sample size =12  
Level of significance=0.2  
Degree of freedom =11  
          
t critical value is (by using t table)=   1.3634
          
Confidence interval formula is

=(101.94,106.56)          

Therefore, The 80​% confidence interval is from ​$ 101.94 to ​$ 106.56