Finding the Lower Quartile: Definition & Example Video

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Interquartile Range: Definition, Formula & Example

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
 Replay
Your next lesson will play in 10 seconds
  • 0:04 Quarters & Quartiles
  • 0:31 Strategies
  • 1:02 Example 1
  • 1:39 Example 2
  • 2:14 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Timeline
Autoplay
Autoplay
Speed Speed

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Mia Primas

Mia has taught math and science and has a Master's Degree in Secondary Teaching.

In this lesson, you'll learn the definition of lower quartile and what it represents in a set of data. You'll review a few examples and follow the steps of finding the lower quartile, then you can take a brief quiz to test what you've learned.

Quarters & Quartiles

To understand what the lower quartile is, we first need to understand what a quartile is. The root of the word quartile is 'quart,' which means one fourth. When we're dividing a set of data into quartiles, we're doing the same thing as dividing a dollar into four quarters. Or, if you are a sports fan, you can think of each quarter of a basketball game. The lower quartile is the first fourth, or the lowest 25%, of the data. It's like the first quarter of a basketball game.

Strategies

To find the lower quartile of a set of data, we can find the median of the data and then find the median of the first half. This strategy is similar to dividing a cake into halves, and then dividing one of the halves in half so that you end up with a quarter of the cake.

Another strategy involves using the following formula, where Q1 is the lower quartile and n is the number of values in the set of data. This formula does not give you the value of the lower quartile, but tells you what term it is in when the data is ordered:

Q1=1/4(n+1)

Example 1

We are given the following set of data. Let's find the lower quartile:

3, 5, 7, 9, 14, 16, 22

Using the first strategy, we would first find the median of the entire set of data, which is 9. Then we would find the median of the values below 9. That would leave us 5 as our lower quartile.

To unlock this lesson you must be a Study.com Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use Study.com

Become a Study.com member and start learning now.
Become a Member  Back
What teachers are saying about Study.com
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account
Support