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 has a sister?
Has a sister: 6, 2
Does not have a sister: 7, 5
Has a brother: 6, 7
Does not have a brother: 2, 5
To find the probability that a student chosen randomly from the class has a sister, we look at the number of students who have a sister (6) and divide it by the total number of students in the class:
Probability of having a sister = Number of students with a sister / Total number of students
= 6 / (6+2+7+5)
= 6 / 20
= 0.3
Therefore, the probability that a student chosen randomly from the class has a sister is 0.3 or 30%.
To find the probability that a student chosen randomly from the class has a sister, we need to calculate the ratio of the number of students with a sister to the total number of students.
The number of students who have a sister is given by the sum of the two values in the "Has a sister" row: 6 + 2 = 8.
The total number of students is given by summing all the values in the data table: 6 + 2 + 7 + 5 = 20.
So, the probability that a student chosen randomly from the class has a sister is 8/20, which can be simplified to 2/5 or 0.4.