Continuous Probability Distributions - Specialty Toys Case Study

I have been doing relatively well with my statistics course. In preparation for my final next week, my teacher has given us some example cases to practice, in preparation for the final. The following case study was given and I must admit, I am a little stumped. I think I need to find the standard deviation in order to compute the probability of the stock out for the order. However, I'm unclear as to what the mean is in order to calculate the standard deviation and z scores.

A thorough explanation of the steps needed to achieve a solution for each of the managerial questions attached will be appreciated. This will assist me in reviewing the case study and finding out which area I am weakest in. Thanks!

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