Q1. The mean number of hours of flying time for pilots at Continental Airlines is 49 hours per month. Assume this mean was based on actual flying times for a sample of 100 Continental Pilots and that the sample standard deviation was 8.5 hours.
A. At 95% confidence, what is the margin of error?
B. What is the 95% confidence interval estimate of the population mean flying time for the pilots?
C. The mean number of hours of flying time for pilots at United Airlines is 36 hours per month. Use your results from part b to discuss the differences between flying times for the pilots at the two airlines. The Wall Street Journal reported United Airlines as having the highest cost among all airlines. Does the information in this exercise provide insight as to why United Airlines might expect higher labor costs?
Q2. Three megapixel digital cameras are typically the lightest, most compact, and easiest to use. However, if you plan to enlarge or crop images, you will probably want to spend more for a higher-resolution model. The data on the exam's Excel worksheet shows sample prices of five megapixel and three megapixel digital cameras.
We would like to test to see if the average price of five megapixel cameras is more than the average price of three megapixel cameras at a 99% confidence level. Assume the camera prices are normally distributed.
a. Provide the hypotheses to be tested
b. What is the p-value?
c. What is your conclusion?
Q3. A mining company made some changes to their mining process in an attempt to save fuel. Before the changes were made, it took an average of 20 gallons of diesel fuel to mine 1,000 pounds of copper. Suppose the standard deviation of fuel used per 1,000 pounds of copper mined is 6 gallons. After the changes were made, the company only used an average of 18 gallons of diesel for the next 30,000 pounds of copper mined.
a. What is the probability to get a sample average of 18 gallons or less for 30,000 pounds of copper mined if the changes to the mining process had no effect?
b. Do you think the changes in the mining process actually lowered the fuel used?
Q4. The owner of a large car dealership believes that the financial crisis decreased the number of customers visiting her dealership. The dealership has historically had 800 customers per day. The owner takes a sample of 100 days and finds the average number of customers visiting the dealership per day was 750. Assume that the population standard deviation is 350.
a. Specify the population parameter to be tested.
b. In order to determine whether there has been a decrease in the average number of customers visiting the dealership daily, the appropriate hypotheses are _________
c. Calculate the value of the test statistic.
d. What is the p-value?
e. At the 5% significance level, what is your conclusion?
Q5. Is your favorite TV program often interrupted by advertising? CNBC presented statistics on the average number of programming minutes in a half-hour sitcom. The data to the right (in minutes) is representative of their findings. Assume the population is approximately normal.
a. What is the point estimate for the mean programming minutes?
b. Construct a 95% confidence interval for the mean number of programming minutes during a half-hour television sitcom.
c. Construct a 99% confidence interval for the mean number of programming minutes during a half-hour television sitcom.
d. Interpret the results for each interval.
Attachment:- Assignment File.rar