<h2>Standard Deviation (SD)</h2>
<p>This parameter measures the spread of answers in the response population. If all users
-answers the same, then SD=0. SD is calculated as the statistical stadard deviation for the
+answers the same, then SD=0. SD is calculated as the statistical standard deviation for the
sample of fractional scores (achieved/maximum) at each particular question.</p>
<h2>Discrimination Index (DI)</h2>