Problem 2 :

400 students are registered in a first-year economics program . the grades of the student in the introductory statistics course typically follow a Normal distribution N,(70,20)

1- In this program , students fail courses if there is below 45 .find the percentage of students that might expect to fail the introductory statistics course .

2- The instructor of this course wants to set up A such that 20% of students who have the highest grades have as . what grade threshold should she use then?