Question 1

In a poll of 900 voters in a campaign to eliminate non-returnable beverage containers, 510 of the voters were opposed. Develop a 94% confidence interval estimate for the PROPRORTION of all the voters who opposed the container control bill.

Question 2

A random SAMPLE of 20 airline pilots had an average yearly income of $99,400 with a SAMPLE STANDARD DEVIATION of $12,000.

1. If we want to determine a 90% confidence interval for the average yearly income, what is the value of t? What are the degrees of freedom?
2. Develop a 90% confidence interval for the average yearly income of all pilots.

Question 3

In order to determine the average weight of carry-on luggage by passengers in airplanes, a sample of 252 pieces of carry-on luggage was collected and weighed. The average weight was 30 pounds. Assume that we know the POPULATION standard deviation of the to be 5.5 pounds.

1. Determine a 99% confidence interval estimate for the mean weight of the carry-on luggage.

Question 4

A statistician employed by a consumer testing organization reports that at 95% confidence he has determined that the true average content of the bottledUncola soft drinks is between 15.85 to 16.15 ounces. He further reports that his sample revealed an average content of 16 ounces, but he forgot to report the size of the sample he had selected. Assuming the standard deviation of the population is 0.25, determine the size of the sample.