A conditional probability asks for a chance after you already know which group the selected person belongs to. Wording such as “selected from” or “who does not participate” tells you to use that group’s total as the denominator. Find the cell where that group meets the requested trait, then divide. Using a total from another row or column changes the question.
Hints
- Hint 1
A condition is something already known about the selected person, so it limits who could be picked. Which column contains the employees who do not participate, and what total is at the bottom of it?
- Hint 2
The favorable count is the number of people who meet both requirements: they do not participate and they work remotely. Find where that column and the remote-workers row meet.
Step-by-step
Restrict to the given group
Step 1Choose the group you can pick from
The phrase does not participate is a condition: it limits who could be selected. The known group sets the denominator. So use the at the bottom of that column, not the employees in the whole table.
- Step 2
Find the remote workers in that group
You want a remote worker from the group that doesn't participate. The remote-workers row and the do-not-participate column meet at , so is the favorable count.
- Step 3
Divide the favorable count by the group total
Probability is favorable picks divided by possible picks. Type in Desmos. It shows about ; tap the fraction button to see . So the probability that the selected nonparticipant is a remote worker is . Choice B.