--- loncom/html/adm/help/tex/Statistics_Overall_Key.tex	2004/01/28 14:36:49	1.1
+++ loncom/html/adm/help/tex/Statistics_Overall_Key.tex	2005/01/10 18:01:30	1.5
@@ -1,41 +1,63 @@
 \label{Statistics_Key}
 
-The \textbf{Overall Problem Statistics} page displayes the following 
+The \textbf{Overall Problem Statistics} page displays the following 
 data about the problems currently in the course:
 
 \begin{itemize}
 
-\item \textbf{#Stdnts}
+\item \textbf{\#Stdnts}
+
 Total number of students attempting the problem.
 
 \item \textbf{Tries}
+
 Total number of attempts to solve the problem.
 
 \item \textbf{Max Tries}
-Largest number of to solve the problem by a student.
+
+Largest number of attempts to solve the problem by a student.
 
 \item \textbf{Mean Tries}
-Average number of tries.
+
+Average number of attempts.
 
 \item \textbf{S.D. tries}
+
 Standard Deviation of the tries.
 
 \item \textbf{Skew Tries}
+
 Skewness of the students tries.
-\[\frac{\sqrt{ \sum{(Xi - Mean)^3} / #Stdnts}}{\sigma^3}\]
+\[\frac{\sqrt{ \sum{(Xi - Mean)^3} / \#Stdnts}}{\sigma^3}\]
 
-\item \textbf{DoDiff}
-Degree of Difficulty of the problem.  
-\[ 1 - \frac{\#YES+\#yes}{Tries} \]
+\item \textbf{\#YES}
 
-\item \textbf{#YES}
 Number of students who solved the problem correctly.
 
-\item \textbf{#yes}
+\item \textbf{\#yes}
+
 Number of students who solved the problem by override.
 
 \item \textbf{\%Wrng}
+
 Percentage of students who tried to solve the problem but were unable to.
 
+\item \textbf{DoDiff}
+
+Degree of Difficulty of the problem.  
+\[ 1 - \frac{\#YES+\#yes}{Tries} \]
+
+\item \textbf{DoDisc}
+
+Degree of Discrimination of the problem.
+
+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.  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
+all of the good students got the problem wrong and the bad students did
+well.
 
 \end{itemize}