A study by Allstate Insurance Co. finds that 82% of teenagers have used cell phones while driving (the Wall Street Journal, May 5, 2010). Suppose a random sample of 100 teen drivers is taken. True or False: The sampling distribution of the sample proportion is approximately normal.

A random sample is drawn from a population with mean μ = 66 and a standard deviation σ =5.5Calculate the probability that the sample mean falls between 66 and 68 for n = 36. 

Last year, the typical college student graduated with $27,300 in debt (The Boston Globe, May 27, 2012). Let debt among recent college graduates be normally distributed with a standard deviation of $6,000.What is the probability that the average debt of two recent college graduates is more than $33,000? 

Unless otherwise specified, round all answers to 4 decimal places!

A car manufacturer is concerned about poor customer satisfaction at one of its dealerships. The management decides to evaluation the satisfaction surveys of its next 40 customers. The dealer will be fined if the number of customers who report favorably is between 22 (out of 40) and 26 (out of 40).The dealership will be dissolved if fewer than 22 (out of 40) customers report favorably. It is know that 70% of the dealer’s customers report favorably on satisfaction surveys.What is the probability that the dealer will be fined?

A study by Allstate Insurance Co. finds that 82% of teenagers have used cell phones while driving (the Wall Street Journal, May 5, 2010). Suppose a random sample of 100 teen drivers is taken.Calculate the standard error for the sampling distribution of the sample proportion. 

According to a  survey, high school girls average 100 text messages daily (The Boston Globe, April 21, 2010). Assume the population standard deviation is 20 text messages. Suppose a random sample of 50 high school girls is taken.What is the probability that the sample mean is less than 95? 

A study by Allstate Insurance Co. finds that 82% of teenagers have used cell phones while driving (the Wall Street Journal, May 5, 2010). Suppose a random sample of 100 teen drivers is taken.What is the probability that the sample proportion is less than .80?

Last year, the typical college student graduated with $27,300 in debt (The Boston Globe, May 27, 2012). Let debt among recent college graduates be normally distributed with a standard deviation of $6,000.What is the probability that the average debt of two recent college graduates is more than $28,000? 

Trader Joe’s is a privately held chain of specialty grocery stores in the United States. Starting out as a small chair of convenience stores, it has expanded to over 340 stores as of June 2010 (http://Tradejoe.com). It has developed a reputation as a unique grocery store selling products such as gourmet foods, beer and wine, bread, nuts, cereal, and coffee. On of their best-selling nuts is Raw California Almonds, which are prices at $4.49 for 16 ounces. Since it is impossible to pack exactly 16 ounces in each packet, a researcher has determined that the weight of almonds in each packet is normally distributed with a mean of 16.01 ounces and a standard deviation of 0.08 ounces. True or False:  The sampling distribution of the sample mean is approximately normal based on any given sample size.