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Statistics

I simply need help with setting up the formula or an example of how to complete the problem on my own. I have been reading the topics but nothing explained what formula to use to get the answer so can someone please show me the steps so I can compute it myself.

1.) The distribution of weights for a sample of 1,400 cargo containers is somewhat normal. Based on the Empirical Rule, what percent of weights will be A.) Between the mean and plus or minus twice the standard deviation, B.) Between teh mean and minus one standard deviation, and C.) Between the mean and three standard deviation

2.) Dan Woodard is the owner and manager of Dan's Truck Stop. Dan offers free refills on all coffee orders. He gathered the following information on coffee refills: there is a 30% chance that a customer will not get a refill, a 40% chance that a customer will get one refill, a 20% chance that a customer will get two refills, and a 10% chance that a customer will get three refills. How many refills can Dan expect a customer to get?

3.) WNAE finds that the distribution fo the length of time listeners are tuned to the station is normal, with a mean of 15 minutes and a standard deviation of 3.5 minutes. What is the probability that a particular listener will tune for. A.) More than 20 minutes
B.) For 20 minutes, or less
C.) Between, 10 and 12 minutes

4.) The monthly sales of muffles in Richmond, VA area follow a normal distribution, with a mean of 1,200 and a standard deviation of 225. The manufacturer want to establish inventory levels such that there is no more than a 5% chance of running out of stock. What level should the manufacturer select as the minimum inventory level?

Solution Preview

(1) (A) Percentage of the weights between mean and plus or minus two standard deviations = 100 * P(-2 < z < 2)

= 100 * 0.9545 = 95.45%

(B) Percentage of the weights between mean and minus one standard deviation = 100 * P(-1 < z < ...

Solution Summary

The distribution of weights for samples are determined.Complete, Neat and Step-by-step Solutions are provided.

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