The Effects of Outliers on Average December 14,2020

 The Effects of outliers on average

Here is a review of what you have learned already:

1. What are mean, median, and mode? They are measures of central tendency or averages.
2. What is the mean of a set of numbers? It is the sum of data values divided by the number of data values. 
3. What is the median of a set of numbers? It is the middle number when numbers are arranged in order.
4. What if there is an even number of numbers? The median is the mean of the two middle numbers.
5. What is the mode of a set of numbers? It is the number that occurs most often.
6. Is there always one mode? No, there may be more than one mode or there may be no mode. 
7. What is the range of a set of numbers? It is the difference between the greatest number and the least number. 

Outlier: a number in a given set of data that is significantly different from the other numbers. 

An outlier is much greater than or much less than most of the numbers in a data set. 

Outliers sometimes occur as a result of error in measuring or recording. In these cases , outliers should be ignored.

Sometimes an outlier is an important piece of information that should not be ignored. For example, if a student does much better or much worse than the rest of the class on a test.

Outliers may not always be obvious . Identifying outliers is then a matter of choice.  Watch the video below.

Example: 21,23,24,24,27,29,29,29,32,37,37,38,3940,50,50,51,54,56,57,58,59,61,71,80,99

How many students are in the class? Count the total number of marks= 26.

What is the outlier? Explain your choice? There is only one number 99, that is significantly different.  The outlier is 99.