Each choice below shows a suggested probability distribution

Each choice below shows a suggested probability distribution for letter grades in a class (Possible grades are A, B, C, or D or lower). Determine which a proper probability distribution is. (0.5 point)

a) A: 10%, B: 0.20, C: 0.50, D or lower: 0.10

b) A: 30%, B: 0.30, C: 0.30, D or lower: 0.30

c) A: 0.30, B: 0.30, C: 0.40, D or lower: 0

d) A: 20%, B: 0.40, C: 0.50, D or lower: -0.10

Solution

The proper probability distribution is A:0.30, B:0.30,C:0.40, D or lower :0

Therefore, the correct option is C