Probability Questions & Answers

Probability Questions & Answers A deck of playing cards has 52 cards, of which 12 are face cards. If you shuffle the deck well and turn over the top 3 cards, one after the other, what's the probability that all 3 are face cards? - ANSWER: 0.010 Since you turn one after another, you are NOT replacing. (12/52)(11/51)(10/50) A plumbing contractor obtains 60% of her boiler circulators from a company whose defect rate is 0.005, and the rest from a company whose defect rate is 0.010. What proportion of the circulators can be expected to be defective? If a circulator is defective, what is the probability that it came from the first company? - ANSWER: .0070, .429 A soft drink dispenser can be adjusted to deliver any fixed number of ounces of soft drink. If the machine is operating with a standard deviation in delivery equal to 0.3 ounces, what should be the mean setting so that a 12-ounce cup will overflow less then 1% of the time? Assume a normal distribution for ounces delivered. - ANSWER: 11.30 ounces x = 12 stDev = 0.3 Mean = ?????...................................................