INTRODUCTION TO OPERATING SYSTEMS
STATISTICS AND HISTOGRAMS

Last change : 11/20/95
Includes : Midterm 2, Midterm 1, homeworks 1 and 2.
(email questions to bolazar@top)

*****************
**  MIDTERM 2  **
*****************

CIS 657 (49 students)
---------------------
min: 33.00; max: 69.00; mean: 55.63; std. dev.: 9.99
median (middle value): 60.00; mode (most frequent value): 65.00

   30.00 |
   35.00 |****
   40.00 |**
   45.00 |****
   50.00 |***
   55.00 |********
   60.00 |******
   65.00 |*******************
   70.00 |***
         0    .    :    .    :

CIS 400 (12 students)
---------------------
min: 28.00; max: 57.00; mean: 43.33; std. dev.: 8.25
median (middle value): 43.00; mode (most frequent value): 45.00

   25.00 |
   30.00 |*
   35.00 |*
   40.00 |**
   45.00 |****
   50.00 |*
   55.00 |**
   60.00 |*
         0    .

*****************
**  MIDTERM 1  **
*****************

CIS 657 (48 students)
---------------------
min: 42.00; max: 95.00; mean: 76.94; std. dev.: 13.38
median (middle value): 77.00; mode (most frequent value): 93.00

   40.00 |
   45.00 |*
   50.00 |**
   55.00 |*
   60.00 |***
   65.00 |*
   70.00 |*****
   75.00 |*******
   80.00 |********
   85.00 |***
   90.00 |********
   95.00 |*********
  100.00 |
         0    .    :

CIS 400 (12 students)
---------------------
min: 49.00; max: 78.00; mean: 67.08; std. dev.: 10.11
median (middle value): 70.00; mode (most frequent value): 72.00 (ambiguous)

   48.00 |
   52.00 |**
   56.00 |*
   60.00 |
   64.00 |*
   68.00 |
   72.00 |****
   76.00 |**
   80.00 |**
         0    .

> Previously, I made the mistake of putting the two CIS400 and CIS657 data
> together, which gave the following statistics :
> 
> min: 42.00; max: 95.00; mean: 74.97; std. dev.: 13.38
> median (middle value): 76.00; mode (most frequent value): 78.00
> 
> But this is not very useful, because 12 students here are graded out of 80
> while 48 others are graded out of 100!

************
**  HW 1  **
************

The statistics of the homeworks include 0's.

min: 0.00; max: 20.00; mean: 15.05; std. dev.: 5.98
median (middle value): 17.00; mode (most frequent value): 20.00

    0.00 |*****
    2.00 |
    4.00 |
    6.00 |***
    8.00 |**
   10.00 |*
   12.00 |**
   14.00 |*********
   16.00 |*****
   18.00 |***********
   20.00 |************************
         0    .    :    .    :    .


************
**  HW 2  **
************

min: 0.00; max: 10.00; mean: 8.24; std. dev.: 2.62
median (middle value): 9.00; mode (most frequent value): 9.00

    0.00 |*****
    1.00 |
    2.00 |
    3.00 |
    4.00 |*
    5.00 |
    6.00 |
    7.00 |***
    8.00 |*****
    9.00 |**********************************
   10.00 |**************
         0    .    :    .    :    .    :    .

Moral to the histogram : Hand in your homeworks. It makes a difference.
                         (you don't have to perfect your answers)