OUTLIER

Outlier

Definition Of Outlier

An outlier is an element of a data set that distinctly stands out from the rest of the data.

Examples of Outlier

An outlier in the list 212, 361, 201, 203, 227, 221, 188, 192, 198 is 361
An outlier in the list 14, 9, 17, 19, 42, 22, 35, 99, 32, 2 is 99

Video Examples: Statistics - How to find outliers

Solved Example on Outlier

Ques: Identify the outlier of the data set. 216, 403, 203, 210, 227, 220, 190, 194

Choices:

A. 403
B. 216
C. 210
D. 220
Correct answer: A

Solution:

Step 1: An outlier is an element of a data set that distinctly stands out from the rest of the data.
Step 2: In the given data set, 403 is far apart from the remaining data values.
Step 3: So, the outlier of the data set is 403.

Quick Summary

An outlier is a value far from the other values in a set of data.
Outliers can skew the mean of a data set.
Outliers can be identified visually or using mathematical rules (e.g., 1.5 x IQR rule).

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🍎 Teacher Insights

Use real-world examples to illustrate outliers (e.g., salary data, exam scores). Discuss the implications of removing or retaining outliers in different contexts.

🎓 Prerequisites

Basic arithmetic
Understanding of data sets
Mean and Median (recommended)

Check Your Knowledge

Q1: Which of the following numbers is an outlier in the dataset: 5, 7, 9, 11, 35?

A. 5 B. 9 C. 11 D. 35

Q2: What is a key characteristic of an outlier?

A. It is the average value. B. It is close to the median. C. It is far from most other data points. D. It always represents an error.

Frequently Asked Questions

Q: How do you identify an outlier?
A: Outliers can be identified visually by inspecting a data plot or using quantitative methods such as the IQR (Interquartile Range) rule or z-score.

Q: What effect does an outlier have on the mean?
A: Outliers can significantly affect the mean, pulling it towards the outlier's value. This makes the mean less representative of the 'typical' value in the data set.