Warm Up

Andrew Dickinson

Imagine you randomly select a student from a large class. We’re interested in their final course grade. Here’s a possible breakdown of how the grades are distributed:

Grade	Percentage of Students
A	20%
B	35%
C	25%
D	15%
F	5%

Q01. If you pick one student at random, what is the probability that the student received at least a B grade?

Probability of at least a B grade: To get at least a B, the student could have received a B, C, D, or F. Sum the probabilities of these grades: \(35\% + 25\% + 15\% + 5\% = 80\%\)

Q02. What is the probability that a randomly chosen student did not receive an A?

Probability of not receiving an A: This is the opposite (or complement) of getting an A. Since the probabilities must add up to 100%, the probability of not getting an A is \(100\% - 20\% = 80\%\)