A professor pays 25 cents for each blackboard error made in lecture to the student who pointsout the error. In a career ofnyears filled with blackboard errors, the total amount in dollarspaid can be approximated by a Gaussian random variableYnwith expected value 40nandand variance 100n. a. What is the probability thatY20exceeds 1000?(b) How many years n must the professor teach in order that P(Y_n > 1000) > 0.99?
