Re: Blackboard

[Greg Clements <clements@MAIL.MLC.EDU>]

Our school uses Blackboard 6.  The standard deviation reported by Blackboard
is not correct.  I checked one of my exams.  Blackboard reports a standard
deviation of around 2.  My statistics calculator computes a value near 13.
The mean reported by Blackboard is correct.  n=24 for my class.

I use the gradebook feature so students can check their current grade.  I
post points earned for the exam, homework and lab for each exam.  I give 5
exams per semester so I will eventually have 15 columns.  The point values
for homework and lab reports are typically different for each unit.  In my
grading scheme a test point, lab point and homework point all make the same
contribution towards the final course grade.  I use the "Weight by Item"
option and Blackboard computes the correct % score ( "Weighted Total" in
Blackboard's terminology ) for each student.

Blackboard does not calculate the correct % score for my classes when
"Weight by Category" is selected.  Blackboard expects all of the items in a
certain category (e.g. homework) to have the same point value.  This is
documented in the Blackboard user guide.  I am not complaining about the
operation of "Weight by Category" but I felt users on this list should be
alerted to, or reminded of, the operation of the "Weight by Category"
calculation.

I would welcome feedback from other Blackboard users on the operation of the
Gradebook.  At midterm and the end of the semester I always export the
Blackboard gradebook to Excel and check the course grade ( % of points
available) that Blackboard calculates.


Greg Clements
Midland Lutheran College
Fremont, NE

----- Original Message -----
From: "Ludwik Kowalski" <kowalskil@MAIL.MONTCLAIR.EDU>
To: <PHYS-L@lists.nau.edu>
Sent: Monday, November 10, 2003 3:26 PM
Subject: BlackBoard users


> BlackBoard, now version 6, is a popular
> software package for teaching over the
> Internet. I am using its quiz and grade book
> tools to supplement face-to-face interactions.
>
> To my horror I discovered that while the mean
> grade calculated by Blackboard (for any given
> column) is correct the corresponding standard
> deviation is much too small. It would be a
> disaster if scores were turned into letter grades
> by using their standard deviation. How comes
> that such bug has not been discovered years
> ago?