MkGrd(Tab,Wts,GdWts=numeric(0),Rnd=T)

 This function sums (optionally weighted) means of specified grade
 types to form a grade.


 Tab   is a gradebook, such as returned from GBget


 Wts   is a list identifying how to weight each different grade
       type; the weights must sum to one.  The names of each
       element are taken from the gradebook column names without
       any numbers.  An example is

           Wts = list(H=0.2, L=0.2, E=.3, F=.3)

       which specifies that homeworks are worth 20%, labs 20%,
       exams (average exam score) is work 30% and the final is worth
       30%.


 GdWts is an optional list describing how to weight *individual* grades.
       Each element must either be a numeric scalar or vector.  If
       it is a scalar, then all grades of the specified type are
       scaled by that quantity.  If it is a vector, then there must
       be one element for each grade of that type.

       For example, 

            GdWts = list(L=100, E=100/c(100,150))

       specifies that labs should be scaled up by a factor of 100
       (appropriate if the labs are entered as zero-one) and that
       the second exam score should be scaled down by a factor of
       0.66667 (appropriate if the second exam was out of 150
       points, but the two exams have equal value).


 Rnd   If rnd is true, the grades are rounded to the nearest
       integer. 

 $Id: GdBkUtil.S,v 1.5 2000/02/02 21:31:53 nicholst Exp $