Assume that on a standardized test of 100 questions a person

Assume that on a standardized test of 100 questions, a person has a probability of 85% of answering any particular question correctly. Find the probability of answering between 72 and 82 questions, inclusive, correctly. (Assume independence, and round your answer to four decimal places.)

P(72 X 82) =_________

Solution

n =100, p=85% =0.85

P(72 X 82) =P(X 82) -P(X <72)

P(72 X 82) =0.236723 -0.00026

P(72 X 82) =0.236463

P(72 X 82) =0.2365