The ages of the people when they bought their Term life insurance for the first time are given in the following data for males and females.

44   31  37  26  43  38  41  44  40  32  28

Construct a 95% confidence interval for average age μ.

6.  The customer service department of a local gas utility wants to estimate the average length of time between the entry of the service request and the connection of service. A random sample of 10 houses is selected from the records available during the past year. The results recorded in number of days are as follows.

114       78         96         137       78         103       117       126       86         99

Assuming the distribution of time as normal, construct a 95% confidence interval estimate of the average length of time (m)

7. A quality control inspector wants to determine the percentage  of cracked  eggs (not broken, just cracked) sold in a store.  The inspector checked 3 cartoons (36 eggs) of eggs and found two eggs that were cracked.

Determine a 90% confidence interval for the percentage  of cracked  eggs.  

What is the margin of error?

How large the sample size should be to have a 99% confidence with 3% margin of error?