Statistics How To

Problems about picking people from groups or committees are as common in probability and statistics as pajamas at a sleepover. It doesn’t matter whether your problem has doctors and nurses, committees or boards, parents and teachers or some other group of people, this how to will show you the steps you need to take to solve these slightly tricky probability problems.

Sample problem: At a school board meeting there are 9 parents and 5 teachers. 2 teachers and 5 parents are female. If a person at the school board meeting is selected at random, find the probability that the person is a parent or a female.

Step 1: Make a chart of the information given. In the sample question, we’re told that we have 5 female parents, 2 female teachers, 9 total parents and 5 total teachers.

Step 2: Fill in the blank column(s). For example, we know that if we have 9 total parents and 5 are female, then 4 must be male.

Step 3: Add a second total to your chart to add up the columns.

Step 4: Add up the probabilities. In our case we were asked to find out the probability of the person being a female or a parent. We can see from our chart that the probability of being a parent is 9/14 and the probability of being a female is 7/14.

9/14 + 7/14 = 16/14

Step 5:Subtract the probability of finding both at the same time. In our case, we subtract female parents.

16/14 – 5/14 = 11/14

You’re done!

Related posts:

1. How to find the Probability of an Event, Given Another Event
2. How to Find the Probability of Group Members Choosing the Same Thing
3. How to figure out the probability of picking from a deck of cards in probability and statistics
4. How to find the probability of a simple event happening
5. How to solve a question about probability frequency distribution