Question

In a class of students, the following data table summarizes how many students have a

brother or a sister. What is the probability that a student chosen randomly from the
class does not have a sister?
Has a brother Does not have a brother
Has a sister
3
12
Does not have a sister
2.

Answer 1

Explanation:

First we need to calculate how many total students there are. Once we have the total we have to divide the number in the category that we want by the total number of students to calculate the probability of randomly getting a student in that category.

Total Students = 3 + 12 + 2 + 7 = 24 students

Probabilities:

does not have a sister =
`(2 + 7)/(24)` = 0.375 or 37.5% (multiply decimal by 100 to get percentage.

Has a brother =
`(3 + 2)/(24)` = 0.208 or 20.8%

Does not have a brother =
`(12 + 7)/(24)` = 0.7916 or 79.2%

Has a sister =
`(3 + 12)/(24)` = 0.625 or 62.5%