Add intro

Author: kgryte

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

@@ -22,6 +22,23 @@ limitations under the License.
 
 > Compute a moving [corrected sample standard deviation][standard-deviation] incrementally.
 
+<section class="intro">
+
+For a window of size `W`, the [corrected sample standard deviation][standard-deviation] is defined as
+
+<!-- <equation class="equation" label="eq:corrected_sample_standard_deviation" align="center" raw="s = \sqrt{\frac{1}{W-1} \sum_{i=0}^{W-1} ( x_i - \bar{x} )^2}" alt="Equation for the corrected sample standard deviation."> -->
+
+<div class="equation" align="center" data-raw-text="s = \sqrt{\frac{1}{W-1} \sum_{i=0}^{W-1} ( x_i - \bar{x} )^2}" data-equation="eq:corrected_sample_standard_deviation">
+    <img src="TODO" alt="Equation for the corrected sample standard deviation.">
+    <br>
+</div>
+
+<!-- </equation> -->
+
+</section>
+
+<!-- /.intro -->
+
 <section class="usage">
 
 ## Usage