Thread: Help in Checking Over Standard Deviation Problem

The number of defective microprocessor chips per 1000 chips is known to have a normal distribution. If the average number of defective chips is 300 with a standard deviation of 50 for every 1000 chips, what is the probability a batch has more than 700 working chips?

Would the answer be 50.00%?

yes, you want the probability that you are above the mean, which is .5
In these cases the st deviation is unimportant.
But we do know that the number of defectives is an integer based rv, hence it can only be approximately normal.