that either the computer or the desk will be delivered before noon is .9, what is the probability that both will be delivered before noon? 11. A distribution of grades in an introductory statistics class (where A = 4, B = 3, etc) is: X 0 1 2 3 4 P(X) .10 .15 .30 .30 ? a. Find P ( X = 4) b. Find (1 3) PX ≤< c. Find the mean grade in this class. d. Find the standard deviation for the class grades. e. Find the lowest grade 0 X such that 0 ( ) 0.5 PX X ≥< 12. Suppose you have a distribution, X, with mean = 28 and standard deviation =2.1. Define a new random variable Y = 2X + 1. 13. An appliance store is offering a special price on a complete set of kitchen appliances (refrigerator, oven, stove, dishwasher). A purchaser is offered a choice of manufacturer for each component: Refrigerator: Kenmore, GE, LG, Whirlpool Oven: KitchenAid, Samsung, Frigidaire, Kenmore Stove: Electrolux, Hotpoint, GE Dishwasher: Bosch, Silhouette, Premier, Whirlpool Use the product rules to answer the following questions: 14. Suppose that for events A and B, a. Compute b. Are events A and B independent? 15. Inventory for a manufacturer are produced at three different plants, 45% from plant 1, 30% from plant 2, and 25% from plant 3. In addition, each plant produces at different levels of quality. Plant 1 produces 2% defectives, plant 2 produces 5% defectives, and plant 3 produces 8% defectives. a. What is the probability that an item is defective? b. If an item from the inventory is found to be defective, what is the probability that is was produced in plant 2?
16. An urn has 20 blue marbles and 15 red marbles in it. Determine the probability that if 5 marbles are selected, at least two will be blue.
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- Fall '08
- Math, Statistics