During the first year at a university that uses a four-point grading system, a freshman took ten three-credit courses and received two As, three Bs, four Cs, and one D.

Question

During the first year at a university that uses a four-point grading system, a freshman took ten three-credit courses and received two As, three Bs, four Cs, and one D.
a) Compute this student's g.p.a.
What I did : 2+3+4+1/4=2.5
2.5 g.p.a
b) Let the random variable X denote the number of points corresponding to a given letter grade. Find the probability distribution of the random variable X and compute E(X), the expected value of X.
I set up a probability distribution table to help me :
X               A/4                B/3            C/2               D/1
P(x=x)       2                     3               4                    1

then I did this:
2/10 =.2, 3/10 =.3, 4/10=.4, 1/10=.1

then :
(4) * (.2) + (3) * (.3) + (2) * (.4)+ (1) (.1) =  .8+.9+.8+.1=2.6
E(X) = 2.6

Damon · Answer

a) Compute this student's g.p.a.
What ::::YOU:::: did : 2+3+4+1/4=2.5
2.5 g.p.a
==========================
What :::: I :::: did
took TEN, each with a number and a value
[2*4 + 3*3 + 4*2 + 1*1 ] / 10
[ 8 + 9 +8 + 1 ] / 10
26/10
2.6

Note ---- That is what you got for part B. That was not a coincidence.