Suppose the average value on the final exam is 78% with a standard deviaton of 10%. Assume the exam scores are normally distributed.
1) Referring to Final Exam, find the probability that a student scores between 70% and 85%.
2) Referring to Final Exam, find the upper 10% of exam scores.
3) Referring to Final Exam, find a 90% confidence interval for students' exam scores, i. e., find an interval centered at 78 so that 90% of the exam scores fall within the interval.
Please do not just give me an excel spreadsheet with the answers like the last tutor did. I need someone to show me how to find these values, tell me what equations to use, etc.