the marks of 100 students in an examination are normally distributed with mean of 25 marks and a standard deviation of 10 marks. Given that the pass mark is 20, estimate the number of students who passed the examination.

Answer 1

The normal distribution is N(25, 10).

P(X > 20) = .691
So approximately 69.1% passed the exam.

69.1% of 100 students is 69 students.