A poll was conducted that asked 1012 people how many books t

A poll was conducted that asked 1012 people how many books they had read in the past year. Results indicated that x = 14.4 books and s = 16.6 books. Construct a 95% confidence interval for the mean number of books people read. Construct a 95% confidence interval for the mean number of books people read. (Use ascending order. Round to two decimal places as needed.)

Solution

Confidence Interval
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)=14.4
Standard deviation( sd )=16.6
Sample Size(n)=1012
Confidence Interval = [ 14.4 ± t a/2 ( 16.6/ Sqrt ( 1012) ) ]
= [ 14.4 - 1.962 * (0.522) , 14.4 + 1.962 * (0.522) ]
= [ 13.38,15.45 ]