Mrs. Burke’s chemistry class has 115
students, classified by academic year and major, as illustrated in the table. Mrs. Burke randomly chooses one student to collect yesterday’s work.
Mrs. Burke’s Chemistry Class
Academic Year Chemistry Majors Non-Chemistry Majors
Freshmen 9
14
Sophomores 16
17
Juniors 15
14
Seniors 17
13
Step 2 of 2 : What is the probability that she selects a sophomore, given that she chooses a chemistry major? Enter a fraction or round your answer to 4
decimal places, if necessary.
The probability of selecting a chemistry major is the sum of all chemistry majors divided by the total number of students:
Probability of selecting a chemistry major = (9+16+15+17) / 115 = 57 / 115 = 0.4957
The probability of selecting a sophomore chemistry major is given by the number of sophomore chemistry majors divided by the total number of chemistry majors:
Probability of selecting a sophomore chemistry major = 16 / 57 ≈ 0.2807
Therefore, the probability that she selects a sophomore, given that she chooses a chemistry major, is approximately 0.2807.