Assignment week 3-The average number of miles driven on a full tank of gas in a Toyota Corolla before its low-fuel...
Question;1) The;average number of miles driven on a full tank of gas in a Toyota Corolla before;its low-fuel light comes on is 320. Assume this mileage follows the normal;distribution with a standard deviation of 30 miles. What is the probability;that, before the low-fuel light comes on, the car will travel;a) Less;than 330 miles on the next tank of gas?;b) More;than 308 miles on the next tank of gas?;c) Between;305 and 325 miles on the next tank of gas?;d) Exactly;340 miles on the next tank of gas?;2) An;automotive parts dealer needs an estimate of the mean life he can expect from;windshield wiper blades under typical driving conditions. He has already;determined that the standard deviation of the population life is 6 months.;Suppose we select a simple random sample of 100 wiper blades, collect data on;their useful lives, and obtain the following results: n = 100, x-;= 21 months, and ? = 6 months. Because the dealer uses tens of thousands of;these wiper blades annually, he wants to find an interval estimate with a;confidence level of 95%.;3);Cinemark Theaters knows that a certain hit movie ran an average of 84 days in;each city, and the corresponding standard deviation was 10 days. The manager of;the southeastern part of Dallas was interested in comparing the movie?s;popularity in his region with that in all of Cinemark?s other theaters. He;randomly chose 75 theaters in his region and found that they ran the movie an;average of 81.5 days.;a) State;appropriate hypotheses for testing whether there was a significant difference;in the length of the picture?s run between theaters in the southeastern part of;Dallas and all of Cinemark?s other theaters.;b) At a 1%;significance level, test these hypotheses.;4) An;industrial psychologist has a stress test that is used to determine the amount;of stress that managers are under. A value of 80 or higher indicates ?high;stress.? The industrial psychologist believes that the managers at a large;profitable pharmaceutical firm are not under ?high stress? and that the average;stress index is less than 80 for managers of the company. A random sample of 50;managers is selected, and their stress index was recorded. Assume that the;population standard deviation is 10.15. See the file ?Stress Index for;Managers?.;a) Test;that the data support the industrial psychologist?s belief. Use the general;rule of thumb concerning the p value to arrive at a conclusion.;b) What;conclusion would you reach if the significance level was.10?.05?.01?
Paper#51982 | Written in 18-Jul-2015Price : $29