Fix equation

Author: kgryte

lib/node_modules/@stdlib/stats/incr/mmeanvar/README.md

@@ -26,9 +26,9 @@ limitations under the License.
 
 For a window of size `W`, the [arithmetic mean][arithmetic-mean] is defined as
 
-<!-- <equation class="equation" label="eq:arithmetic_mean" align="center" raw="\bar{x} = \frac{1}{n} \sum_{i=0}^{W-1} x_i" alt="Equation for the arithmetic mean."> -->
+<!-- <equation class="equation" label="eq:arithmetic_mean" align="center" raw="\bar{x} = \frac{1}{W} \sum_{i=0}^{W-1} x_i" alt="Equation for the arithmetic mean."> -->
 
-<div class="equation" align="center" data-raw-text="\bar{x} = \frac{1}{n} \sum_{i=0}^{W-1} x_i" data-equation="eq:arithmetic_mean">
+<div class="equation" align="center" data-raw-text="\bar{x} = \frac{1}{W} \sum_{i=0}^{W-1} x_i" data-equation="eq:arithmetic_mean">
     <img src="https://cdn.rawgit.com/stdlib-js/stdlib/563a8587d936008c82db675be84f8ce1474fee27/lib/node_modules/@stdlib/stats/incr/mmeanvar/docs/img/equation_arithmetic_mean.svg" alt="Equation for the arithmetic mean.">
     <br>
 </div>