Question

1. Nina is looking to analyze the distribution of the variable X=’grading. She gathered information from 1900 to 2000, and her data concludes X follows a normal distribution with mean 75 and variance 30.
   1. What is the probability that a typical student from the current cohort enrolled receive a grade above 80?
   2. Between what values will the grades of the 95% of all students in the current cohort fall?
   3. Find the value that represents the 25^th and 75^th percentile of this distribution. Then, find the interquartile range. Can a student who got 45 be considered a potential outlier, explain the reasoning.

Answer 1