1. the j.o. supplies company buys calculators from a korean
1. The J.O. Supplies Company buys calculators from a Korean supplier. The probability of a defective calculator is 20%. If 14 calculators are selected at random, what is the probability that less than 3 of the calculators will be defective?
2. An important part of the customer services responsibilities of a cable of company relates to the speed with which trouble in service can be repaired. Historically, the data show that the probability is 0.30 that troubles in residential services can be repaired on the same day. For the first fifteen troubles reported on a given day, what is the probability that 7 or more troubles will be repaired on the same day?
3. Given the length an athlete throws a hammer is normal random variable with mean 60 feet and standard deviation 4 feet, what is the probability he throws it between 55 feet and 62 feet?
4. If x is a binomial random variable where n=150 and p=0.4, find the probability that X is more than or equal to 55 using the normal approximation to the binomial.