
sample size?
at a plant the productionrates vary with a mean of 0.84 and a standard deviation of 0.01. a line supervisor confirmed that the production rate variation follows a normal distribution. a plant wants to produce a batch of parts and wants to be 99% sure that they will have X good parts in the end. How many parts shall they begin with? Only one batch can be runned.

Are you stating the problem asis or are you paraphrasing? This problem doesn't really make sense. Production rate usually refers to the number of objects that you produce in a given time. Part of the problem is talking about rate of production and the other is talking about defective rates. And what does it mean to have a normally distributed nondefective rate of 0.84 with a standard deviation of 0.01? You could say that the nondefective rate of producing N items is normally distributed with mean 0.84 with a standard deviation of 0.01. But then we would need to know that number N.