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Can you help me understand how to do these 3 problems? Be specific, please. Here is my homework, word for word: Here we are given the probability, say .9 and we find the values of the random variable (-a and a) that determine a probability of .9 on a standard normal distribution...

Hello, EDIT: I am having trouble uploading my .xls file. I also tried putting the .xls into a .zip but I will always receive an error message. How can I solve this? I am a college student and have just started my first class of statistics. I am quite good at math (taking calculus) but I am...