in a class of students, the following data table summarizes how many students have a brother or a sister…

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 who does not have a sister has a brother?\n| |has a brother|does not have a brother|\n|--|--|--|\n|has a sister|4|9|\n|does not have a sister|2|15|

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 who does not have a sister has a brother?\n| |has a brother|does not have a brother|\n|--|--|--|\n|has a sister|4|9|\n|does not have a sister|2|15|

Answer

Explanation:

Step1: Find number of students without sister

We sum the number of students in the "Does not have a sister" row. So, $2 + 15=17$.

Step2: Find number of students without sister and with brother

The number of students without a sister and with a brother is 2.

Step3: Calculate the conditional - probability

The probability that a student who does not have a sister has a brother is the number of students without a sister and with a brother divided by the number of students without a sister. So, $P=\frac{2}{17}$.

Answer:

$\frac{2}{17}$