2. On a recent Statistics test the grades were normally distributed. 68% of the students scored between an 80 and a 90. There are 150 students taking statistics. (a) What is the mean for the distribution of grades in this course?

(b) What is the standard deviation for distribution of grades?

(c) What is the z score for a student who scores a 95?

(d) What is the z score for a student who scores a 28?

(e) What are the maximum and minimum for the central 68% of students’ scores?

(f) What are the maximum and minimum for the central 99.7% of students’ scores?

(gi) What % of the students scored above 90?

(h) What % of students passed the exam (greater than a 70)?

(i) How many students passed the exam?

(j)What is the grade of a student at the 80th percentile?

(i) What is the grade of a student at the 50th percentile?

(k) How many of the students scored between 80 and 90? (hint: first, find the percentage)