--- loncom/html/adm/help/tex/Statistics_Overall_Key.tex	2006/08/08 17:47:27	1.8
+++ loncom/html/adm/help/tex/Statistics_Overall_Key.tex	2014/05/27 18:06:24	1.11
@@ -1,4 +1,4 @@
-\label{Statistics_Key}
+\label{Statistics_Overall_Key}
 
 The \textbf{Overall Problem Statistics} page displays the following 
 data about the problems currently in the course:
@@ -41,7 +41,7 @@ there were no attempts made on the probl
 
 The students are grouped based on their scores on the sequence which 
 contains the homework problem.  The percent score of the bottom 25\% of
-the students is subtracted from the percent score the to top 25\% of
+the students is subtracted from the percent score of the top 25\% of
 the students.  This yields a number from -1 to 1. 1.0 indicates
 all of the good students answered the problem correctly and none of the
 poor students answered it correctly.  Conversely, a score of -1.0 indicates
@@ -77,7 +77,7 @@ problem parts of the selected students o
 
 To compute the KR-21 reliability statistic the following formula is used:
 
-\[KR-21 = \frac{K}{K-1} \cdot \frac{1-(M \cdot (K-M))}{K \cdot s^{2}}\]
+\[KR-21 = \frac{K}{K-1} \cdot \left(1- \frac{M \cdot (K-M)}{K \cdot s^{2}} \right)\]
 
 Where 
 \begin{description}