Skip main navigation

New offer! Get 30% off one whole year of Unlimited learning. Subscribe for just £249.99 £174.99. New subscribers only. T&Cs apply

Find out more

Measures of Spread - Interpreting Standard Deviation

Standard deviation of data gives a lot of information about data that is approximately bell-shaped. Adrian Gepp explains more in this video.

Interpreting Standard Deviation

Standard deviation is an important measure of spread because of how it can be interpreted for data that is approximately bell-shaped. Specifically, it gives an indication of how much is how far away from the mean. If the data is approximately bell shaped then:

  • 68% of the data is within plus or minus one standard deviation around the mean
  • 95% of the data is within plus or minus two standard deviations around the mean
  • 99.7% of the data is within plus or minus three standard deviations around the mean

This result means that standard deviation is a very descriptive statistic! Now that we have some tools for measuring spread, let’s look at how we measure shape in the next step.

This article is from the free online

Data Analytics for Decision Making: An Introduction to Using Excel

Created by
FutureLearn - Learning For Life

Reach your personal and professional goals

Unlock access to hundreds of expert online courses and degrees from top universities and educators to gain accredited qualifications and professional CV-building certificates.

Join over 18 million learners to launch, switch or build upon your career, all at your own pace, across a wide range of topic areas.

Start Learning now