Home
Statistics for Big Data For Dummies
Explore Book
Buy On Amazon

In data analysis, the relationship between the mean and the median can be used to determine if a distribution is skewed. The histogram shows that most of the returns are close to the mean, which is 0.000632 (0.0632 percent). The median is −0.0001179.

Histogram shows most returns close to the mean.
Histogram shows most returns close to the mean.

Here's how to determine whether the distribution is skewed:

image1.jpg

In this case, the distribution of returns to ExxonMobil stock is positively skewed. This means that large positive returns somewhat outweigh large negative returns in this dataset.

You can also use a histogram to determine if a dataset is skewed. For positively skewed data, the right tail tends to be longer than the left tail. The reverse is true for negative skewed data. In the histogram, the right tail of the distribution appears to be slightly longer than the left tail, which provides more evidence that the data is positively skewed.

About This Article

This article is from the book: 

About the book author:

Alan Anderson, PhD is a teacher of finance, economics, statistics, and math at Fordham and Fairfield universities as well as at Manhattanville and Purchase colleges. Outside of the academic environment he has many years of experience working as an economist, risk manager, and fixed income analyst. Alan received his PhD in economics from Fordham University, and an M.S. in financial engineering from Polytechnic University.

David Semmelroth has two decades of experience translating customer data into actionable insights across the financial services, travel, and entertainment industries. David has consulted for Cedar Fair, Wachovia, National City, and TD Bank.