# Outlier

Outlier

The outlier in the literary world refers to the best and the brightest people.

There is a non-fiction book 'Outliers' written by Malcolm Gladwell that debuted as the number one on the best seller books of the New York Times. Here, Malcolm describes outliers as people with exceptional intelligence, large fortunes, and who are different from the usual set of people.

Reflect your thoughts through this below image, with the outliers standing out from the crowd. Now, let's move ahead to understand the concept of an outlier in math.

In this mini-lesson, we shall explore the topic of outliers, by finding answers to questions like what is an outlier, how to find outliers using the turkey method, how to find outliers using the interquartile range, solved examples, and interactive questions at the end.

Let's begin!

## Lesson Plan

 1 What Is an Outlier? 2 Important Notes on Outlier 3 Think Out of the Box! 4 Solved Examples on Outlier 5 Interactive Questions on Outlier

## What Is an Outlier?

The extreme values in the data are called outliers.

Example: For a data set containing  2, 19, 25, 32, 36, 38, 31, 42, 57, 45, and 84 In the above number line, we can observe the numbers 2 and 84 are at the extremes and are thus the outliers.

The outliers are a part of the group but are far away from the other members of the group.

The problem with outliers: Outliers create an imbalance in the data-set and hence are generally removed from the data. Also, sometimes the outlier occurs in the data-set, due to an error.

Consider the data:  70, 73, 77, 71, 7, 73, 72, and 78

Let's calculate the mean to understand how the outlier affects the results.

Here, the datapoint 7, is an outlier.

Mean (with outlier) $$= \dfrac{70 + 73 + 77 + 71 + 7 + 73 + 72 + 78}{8} = \dfrac{521}{8} = 65.1$$

Mean (without an outlier) $$= \dfrac{70 + 73 + 77 + 71 + 73 + 72 + 78}{7} =\dfrac{514}{7} = 73.4$$

We can now observe how the outlier creates a variation in the mean value of the data.

Before we learn about finding the outlier, let's know about the quartiles and interquartile range.

More Important Topics
Numbers
Algebra
Geometry
Measurement
Money
Data
Trigonometry
Calculus
More Important Topics
Numbers
Algebra
Geometry
Measurement
Money
Data
Trigonometry
Calculus
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