Lunch breaks are often considered too short and employees fr

Lunch breaks are often considered too short, and employees frequently develop a habit of \"stretching\" them. The manager at Giant Mart randomly identified 22 employees and observed the length of their lunch breaks (in minutes) for one randomly selected day during the week.

(b) Find the 95% confidence interval for \"mean length of lunch breaks\" at Giant Mart. (Give your answers correct to two decimal places.)
________ to  minutes______

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)=29.227
Standard deviation( sd )=5.622
Sample Size(n)=22
Confidence Interval = [ 29.227 ± t a/2 ( 5.622/ Sqrt ( 22) ) ]
= [ 29.227 - 2.0796 * (1.2) , 29.227 + 2.0796 * (1.2) ]
= [ 26.73,31.72 ]