Exam statistics
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Exam 1 statistics 
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       (reported on   10/2/2020)
N              =   35
Interval       =   0-250
Average        =   170
Stand Deviation=    58
Median         =   190
Min range      =   0-70
Max range      = 240-250
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Exam 2 statistics 
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       (reported on   11/9/2020)
N              =   32
Interval       =   0-250
Average        =   175
Stand Deviation=   45
Median         =   191
Min range      =   0-80
Max range      =   230-250
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Exam 3 statistics 
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       (reported on   12/16/2020)
N              =   29
Interval       =   0-360
Average        =   259
Stand Deviation=   62
Median         =   296
Min range      =   0-130
Max range      =   320-350
=================================

The class average is 750 (N=29) 
(It is out of 1020pt including the 20 bonus points)
Standard deviation is 149; roughly half of it define a group
of letter grades (exception is the extremes:A and F that can be wider
and C that starts at 500pt). 
  [Gaps are safety margins that are usually empty]
  [Usually the average 750 falls in the top C+ group but my group
   grading is a bit more generous and falls into the B group]

850-1020 A
690-840  B or B+
500-670  C or C+
400-480  D
 0 -350  F


Definitions     Definitions
===========     ===========
N               =  number of students taking the exam
Interval        =  0 to maxpoints possible for exam (as in Handout 1)
Average         =  Sum of exam grades divided by N
Stand Deviation =  Shows dispersion of grades. Roughly, 2/3 of the grades are
                   within 37 +/- 12 , and 95% within  37 +/-  2*12 if ave is 37 
                   and std 12
Median          =  Half of the students got that much or less 
                   (and half, more than that).