[
https://issues.apache.org/jira/browse/MATH-1398?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Rob Tompkins updated MATH-1398:
-------------------------------
Fix Version/s: 4.X
> Support simple Arithmetic mean without Compute correction factor in second
> pass?
> --------------------------------------------------------------------------------
>
> Key: MATH-1398
> URL: https://issues.apache.org/jira/browse/MATH-1398
> Project: Commons Math
> Issue Type: Improvement
> Environment: All
> Reporter: Francis Li
> Labels: easyfix
> Fix For: 4.X
>
>
> The mean calculate by this function is different excel. which just sum/n as
> first half of function. can we provide another option to calculate normal
> means?
> org.apache.commons.math3.stat.descriptive.moment.Mean
> public double evaluate(final double[] values,final int begin, final int
> length)
> 163 throws MathIllegalArgumentException {
> 164 if (test(values, begin, length)) {
> 165 Sum sum = new Sum();
> 166 double sampleSize = length;
> 167
> 168 // Compute initial estimate using definitional formula
> 169 double xbar = sum.evaluate(values, begin, length) / sampleSize;
> 170
> 171 // Compute correction factor in second pass
> 172 double correction = 0;
> 173 for (int i = begin; i < begin + length; i++) {
> 174 correction += values[i] - xbar;
> 175 }
> 176 return xbar + (correction/sampleSize);
> 177 }
> 178 return Double.NaN;
> 179 }
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
