PROBLEMS Stats Assignment Homework Help


1. Using the binomial formula, compute the probability of exactly r, successes in n trials if (a) r = 3, n = 5, p = 0.6; (b) r = 0, n = 4, P = 0.1; . (c) r = 2, n = 6, p = 0.7; (d) r = 4, n = 8, p = 0.5.
2. (a) Compute and tabulate the binomial distribution for n = 4, P = 0.7. (b) From the table for (a), compute the probability of at least two successes. (c) Make a graph of the distribution.
3. From Table IB, with n = 20 and p = 0.75, compute the probability of (a) less than 15 successes; (b) at least 15 successes; (c) at most 15 successes; (d) from 10 to 15 successes, inclusive; (e) exactly 13 successes.
4. A salesperson has a 10 percent chance of maki ng a sale to any customer who is called upon. If 20 calls are made, what is the chance that (a) fewer than three sales are made? (b) at least one sale is made? (c) more than five sales are made.
5. A true-false test has 50 questions. To pass, a student must get 60 percent or more of the answers correct. What is the chance of passing if a student chooses the answer to each question by tossing a coin and checking true if heads appear and false if tails appear?
6. A town has three ambulances for emergency transportation to a hospital. The probability that anyone of these will be available at a given time is 0.75. If a person calls for an ambulance, what is the probability that an ambulance will be available?
7. The probability that any inspector will properly classify a defective item as defective is 0.7. If a defective is examined independently by two inspectors, what is the chance that neither will classify it correctly?
8. A department store employs five clerks who take orders over the telephone . Each clerk is busy taking an order 80 percent of the time. If three customers call at one time, what is the probability that, at that time, clerks will be available to take (a) all three orders? (b) only two orders?
9. A mail order firm sends out advertisements in batches of 50 at a time. The probability of receiving an order as a result of anyone of the advertisements is 0.05. What is the probability of receiving (a) no orders from a batch? (b) three orders from a batch? (c) at most two orders from a batch? (d) more than four orders from a batch? (e) What is the expected number of orders per batch?
10. (a) How is an acceptance sampling plan with n = 10, a = 2 carried out? That is, what do n = 10 and a = 2 mean? (b) If n = 10, a = 2, what is the chance that a lot which is 10 percent defective will be accepted? (c) If n = 10, a = 2, what is the chance that a lot which is 25 percent defective will be rejected? (d) If n = 20, a = 2, what is the chance that a lot which is 25 percent defective will be rejected?
11. An accep.tance sampling plan with n = 50 is to be used by a company .which considers a lot having 1 percent defective to be a high-quality lot. The company wants the chance of accepting such’ a lot to be as close as possible to 0.99. What should the acceptance number be?
12. In acceptance sampling, what is meant by consumer’s risk and producer’s risk?
13. If 50 percent of all voters actually favor a political candidate, what is the chance that in a sample of n = 50 voters (a) exactly 50 percent (that is, 25) will favor the candidate? (b) less than 50 percent will favor the candidate? . 4 Seventy-five percent of the production workers hired by Griggs Company are good workers. If Griggs hires 20 workers, what is the probability that (a) exactly 15 are good workers? (b) at least 15 are good workers? (c) all 20 are good workers?
15. A space shuttle has independently functioning computers. All tour must be operating properly before the shuttle will be cleared for lift-oft. If the probability of proper operation. is 0.995 for each computer, what is the probability that improper computer operation will delay lift-oft?
16. ILa coin is tossed 20 times: (a) What is the expected nurnberof heads? (b) What is the probability that the number of heads will turn out to be  the expected number?
17. Suppose a binomial distribution has n = 4 and p = 0.3. (a) What is the mean of the distribution? (b) What is the standard deviation of the distribution?


Share the Story

About the Author

Back to Top
Share This