Question 3

A computer chip manufacturer finds that for every 100 chips produced, 85 meet specifica-
tions, 10 need reworking and 5 need to be discarded. Ten chips are chosen for inspection.
(a) What is the probability that all 10 meet specs?
(b) What is the probability that two or more need to be discarded?
(c) What is the probability that 8 meet specs, 1 needs rework and 1 will be discarded?


Solution

a) 85/100*84/99*83/98*82/97*81/96*80/95*79/94*78/93*77/92*76/91

or for all 10 to meet specifications C(10,10) (85)^10 (15)^0


does anybody know if this is the right way to solving the probability questions. I will appreciate your help. Thank you very much.

Leon - the solution is easier than this. Each chip is manufactured indendently from each other, so the probability of each meeting spec is 0.85. Hence the oddsof getting 10 in a row that meet spec is 0.85^10.

Your approach of using 85/100 * 84/99 *.. 76/91 would be appropriate if the problem involved pulling chips from a bucket of 100 wher you are told that there are precisely 85 chips that meet spec, and you want to know the probabilit yof pulling 10 in a row without replacement that meet spec. That's a different problem than you're trying to solve here.

From a standard 52-deck of cards, five cards are chosen. How many five card hands contain a) five hearts
b) five cards of the same suit
c) two kings and three queens

suppose that 5 out of 100 and 25 women out of 10000mare colour-blind.A colour-blind person is chosen at random.What is the probability of his being male?

Please do not tack a new question onto an old post - instead you should start a new thread. But here's a hint: suppose you have a group of 2000 people, consisting of 1000 men and 1000 women. Of that group, how many are expected to be color blind? Now take that group and consider them as their own group of color blind people. Of that group, how many are men, and how many are women? Now, what is the probability that a person chosen at random from the color blind group is male?

A computer chip manufacturer finds that for every 100 chips produced, 85 meet specifica-
tions, 10 need reworking and 5 need to be discarded. Ten chips are chosen for inspection.
(a) What is the probability that all 10 meet specs?
(b) What is the probability that two or more need to be discarded?
(c) What is the probability that 8 meet specs, 1 needs rework and 1 will be discarded?

Digital - why are you copyng a 3-year old question? If you are trying to solve this, please review the earlier posts and try to come up with the answer yourself. If you get stuck someone will help you, but first please show us your attempt.

I think it's pointless...

/Thread Closed