1. 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.
2. 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)
3. 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?