SnowStar757
New member
- Joined
- Nov 7, 2011
- Messages
- 4
Hi, I need help with a few questions, I have attempted them but I am not sure if what I am doing is right..
1. Let X equal the medium outcome when a 8 sided die is rolled five times.
a) Find the p.m.f of X
b) Find the mean and variance of X.
2. In a lot of 12 light bulbs, there are three defective bulbs. If you inspect bulbs one at a time randomly without replacement. How many bulbs do you have to inspect so that the probability of finding at least one defective bulb is at least 80%.
3) An urn contains 6 red chips. Each time a chip is drawn at random and it is replaced by a white chip if the chip drawn is a red chip. What is the expected number of draws needed so that that all of the chips in the urn are white?
6) A lot of 30 parts is shipped to a company. A sampling plan dictates that n parts are to be taken at random without replacement. The lot will be accepted if no more than one of these n parts is defective. What is the minimum value of n such that the probability of accepting the lot is at least 80% if the lot contains 3 defective parts and the probability of accepting the lot is less than 25% if the lot contains 9 defective parts?
Thank you so much
1. Let X equal the medium outcome when a 8 sided die is rolled five times.
a) Find the p.m.f of X
b) Find the mean and variance of X.
2. In a lot of 12 light bulbs, there are three defective bulbs. If you inspect bulbs one at a time randomly without replacement. How many bulbs do you have to inspect so that the probability of finding at least one defective bulb is at least 80%.
3) An urn contains 6 red chips. Each time a chip is drawn at random and it is replaced by a white chip if the chip drawn is a red chip. What is the expected number of draws needed so that that all of the chips in the urn are white?
6) A lot of 30 parts is shipped to a company. A sampling plan dictates that n parts are to be taken at random without replacement. The lot will be accepted if no more than one of these n parts is defective. What is the minimum value of n such that the probability of accepting the lot is at least 80% if the lot contains 3 defective parts and the probability of accepting the lot is less than 25% if the lot contains 9 defective parts?
Thank you so much