Here is part of the same problem with SLIGHTLY Different numbers! But the process is the same!
Step 1
Let X be the weight of a certain brand of candies and the weights are normally distributed with mean 0.8599 g and standard deviation 0.0519 g. A sample of one package of net weight 387.0 g contains 453 candies is taken.
Let X-bar be the sample mean and we have to find the probability that P(X-bar > 0.8542g).
Since the sample size n = 453 is large, by Central Limit Theorem, the sample mean is approximately normally distributed with
Step 2
The required probability is ...