MATH-1178 (typo in userguide)

Fixed incorrect example in "stat" section.
[Reported by Dmitriy.]

src/changes/changes.xml

@@ -73,6 +73,9 @@ Users are encouraged to upgrade to this version as this release not
   2. A few methods in the FastMath class are in fact slower that their
   counterpart in either Math or StrictMath (cf. MATH-740 and MATH-901).
 ">
+      <action dev="erans" type="fix" issue="MATH-1178" due-to="Dmitriy">
+        Fixed example in userguide ("stat" section).
+      </action>
       <action dev="erans" type="fix" issue="MATH-1175" due-to="Karsten Loesing">
         Fixed inverse cumulative probability of 0 in "LaplaceDistribution".
       </action>

src/site/xdoc/userguide/stat.xml

@@ -196,7 +196,7 @@ double std = stats.getStandardDeviation();
 // Compute statistics directly from the array
 // assume values is a double[] array
 double mean = StatUtils.mean(values);
-double std = StatUtils.variance(values);
+double std = FastMath.sqrt(StatUtils.variance(values));
 double median = StatUtils.percentile(values, 50);
 
 // Compute the mean of the first three values in the array