# probability distribution!

• Apr 4th 2013, 12:46 AM
lawochekel
probability distribution!
a manufacturer reports the number of major defects for each new automobile that it test using
certain quality control rule; suppose the number of such defects for a certain model is a
random variable with mean 0.32 and standard deviation 0.24. among 50 randomly selected cars
of this model, how likely is the sample average number defects exceeds 6?

pls help here, how do i begin to tackle this problem right?
• Apr 4th 2013, 02:07 PM
majamin
Re: probability distribution!
Quote:

Originally Posted by lawochekel
a manufacturer reports the number of major defects for each new automobile that it test using
certain quality control rule; suppose the number of such defects for a certain model is a
random variable with mean 0.32 and standard deviation 0.24. among 50 randomly selected cars
of this model, how likely is the sample average number defects exceeds 6?

pls help here, how do i begin to tackle this problem right?

Sample is large enough to assume a normal distribution, so the new mean is $50(0.32)$ and the new standard deviation is $\sqrt{50} (0.24)$. Compute the z-score, and find the probability using a z-score table.