The probabilities of a student getting grade A, B, C and D are 0.2, 0.3, 0.15 and 0.35 respectively. Then the probability that the student gets

1) At least C grade is __________
2) At most C grade is ___________

Waste

To find the probabilities in this scenario, we need to understand the concept of cumulative probability. The cumulative probability refers to the probability of an event occurring up to a certain point.

1) To find the probability of getting at least a C grade, we need to calculate the cumulative probability of getting a C, D, or A grade.

Step 1: Calculate the cumulative probability of getting a C grade or better:
P(C or better) = P(C) + P(D) + P(A)
= 0.15 + 0.35 + 0.2
= 0.7

Therefore, the probability that the student gets at least a C grade is 0.7.

2) To find the probability of getting at most a C grade, we need to calculate the cumulative probability of getting a C grade or lower.

Step 1: Calculate the cumulative probability of getting a grade lower than or equal to a C:
P(C or lower) = P(C) + P(D)
= 0.15 + 0.35
= 0.5

Therefore, the probability that the student gets at most a C grade is 0.5.

At least C = A, B or C

Either-or probability is found by adding individual probabilities.

At most C = F, D or C

Is there no probability of getting an F?

P(F) = 1 - .2 - .3 - .15 - .35 = ?