MA260Statistical Analysis I

Directions: Besure to save an electronic copy of your answer before submitting itto Ashworth College for grading. Unless otherwise stated, answer incomplete sentences, and be sure to use correct English, spelling, andgrammar. Refer to the “Assignment Format” page located onthe Course Home page for specific format requirements.

**NOTE:** Show your work in theproblems.

1. A recent article in the Myrtle Beach Sun Times reportedthat the mean labor cost to repair a color television is $90 with astandard deviation of $22. Monte’s TV Sales and Service completedrepairs on two sets this morning. The labor cost for the first was$75 and it was $100 for the second. Compute **z** valuesfor each and comment on your findings.

2. The mean of a normal distribution is 400 pounds. The standarddeviation is 10 pounds.

a. What is the area between 415 pounds and the mean?

b. What is the area between the mean and 395 pounds?

c. What is the probability of selecting a value at random anddiscovering that it has a value of less than 395 pounds?

3. The monthly sales of mufflers in the Richmond, VA area follow thenormal distribution with a mean of 1200 and a standard deviation of225. The manufacturer would like to establish inventory levels suchthat there is only a 5% chance of running out of stock. Where shouldthe manufacturer set the inventory levels?

4. Research on new juvenile delinquents revealed that 38% of themcommitted another crime.

a. What is the probability that of the last 100 new juveniledelinquents put on probation, 30 or more will commit another crime?

b. What is the probability that 40 or fewer of the delinquents willcommit another crime?

c. What is the probability that between 30 and 40 of the delinquentswill commit another crime?

5. An Air Force study indicates that the probability of a disastersuch as the January 28, 1986 explosion of the space shuttleChallenger was 1 in 35. The Challenger flight was the25th mission.

a. How many disasters would you expect in the first 25 flights?

b. Use the normal approximation to estimate the probability of atleast one disaster in 25 missions.

**Grading Rubric**

Please referto the rubric below for the grading criteria for this assignment.