[MATH-1178] Incorrect sample of usage of StatUtils at homepage

• Type: Bug
• Status: Closed
• Priority: Trivial
• Resolution: Fixed
• Fix Version/s: 3.4

Environment

Documentation at http://commons.apache.org/proper/commons-math/userguide/stat.html

• Assignee: Unassigned
• Reporter: Dmitriy
• Created: 08/Dec/14 22:58
• Updated: 26/Dec/14 19:50
• Resolved: 08/Dec/14 23:17

Description

At http://commons.apache.org/proper/commons-math/userguide/stat.html you are providing three ways to compute mean, std, median with DescriptiveStatistics, SummaryStatistics, StatUtils.
But when you execute double std = StatUtils.variance(values), you are not actually get std in std, you get std*std, because DescriptiveStatistics actually returns FastMath.sqrt(getVariance()), but StatUtils returns variance directly.

The solution is to substitute "double std = StatUtils.variance(values);" with "double std = FastMath.sqrt(StatUtils.variance(values));"