Exploring Interactive Computer
Marked Assessments for Logic
Constructs in Level 1 Computing
Michael Isherwood
Associate Teaching Fellow, COLMSCT
Centre for Open Learning of Mathematics, Science, Computing and Technology (COLMSCT)
Centre for Excellence in Teaching and Learning
The Open University is incorporated by Royal Charter (RC 000391), an exempt charity in England & Wales and a charity registered in Scotland (SC 038302).
Presentation Summary
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Project Aims and Background
The Quizzes
Logical OR Analyses
Results and Student Views
Project Aims - summary
• Support students in their understanding of new and
difficult parts of M150 (in effect, Block 2)
• Confirm understanding prior to tma feedback
• Investigate extension to other computing courses
• Through better understanding, aid retention
Background
• Students find getting to grips with programming difficult
• This leads to frustration and dropping out of M150 (and
therefore further computing courses)
Background - TMA02/03 Marks
On-Line Quizzes
• 6 Quizzes on 2008J and 2009B
presentations
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Structured English
Conditions, truth and trace tables
Basic JavaScript
Selection - the if statement
Repetition - the while statement
Repetition - the for statement
Results following are from 2008J up to March
Example Question Quiz 4 Q2
• 71% correct at 1st attempt
• Only 4% wrong after 3rd
attempt
Note Feedback after
1st attempt
After 2nd attempt the
correct answers
remain, so student
concentrates on
incorrect answer(s)
Logical OR
CP5D A person with body temperature outside the range 35oC to 37oC is
viewed as requiring medical attention. Within this range the temperature
is considered normal. Write a compound condition that evaluates to
true for requiring medical attention, using temp for temperature (in oC)
(temp < 35) OR (temp > 37)
• 24% correct 1st attempt and 43% after 3rd attempt
• Some learning as earlier logical AND only 29% after 3rd attempt
Analysis of OR
On
(temp < 35) OR (temp > 37)
1st
Attempt
AND and
22
5
&&
1
&
0
OR
56
or ||
12 2
¦¦
0
unit
12
%
• 70% correct in principle with 56% absolutely correct
• 28% incorrectly go for AND etc
•12% of responses included unit (g mm nm oC)
Again an improvement on earlier logical AND question where 62%
and 19% are comparative results
No improvement in omitting unit (10% in logical AND) and no
difference between unit depending on familiarity or difficulty
Comparison Operator Analysis
The 5 variants are :
(age<17) OR (age>=60)
(mass<53) OR (mass>=63)
(len<=219) OR (len>=221)
(WL<=400) OR (WL>=700)
(temp<35) OR (temp>37)
• 49% chose < when correct but only 14% chose <= when correct
• 69% chose > when correct but only 28% chose >= when correct
• Some 3% chose =< and/or =>
Interpreting boundary value operators (and values) creates an
issue when having to apply from text –
“with body temperature outside the range 35oC to 37oC”
JavaScript Logical OR Example
SY6D A shop waives address evidence on credit card sales when
the customer's status is that of existing customer or when the
purchase amount is under £40.
In the following compound statement expressing this situation drag
in the symbols required.
< <= = == > >= != AND OR & && ||
( amount
40 )
( status
'existing' )
( amount < 40 ) || ( status == 'existing' )
Note that in JavaScript (as in other programming languages) many
symbols differ from the pseudocode symbols eg || for OR and == for =
JavaScript Logical OR Conclusions
This was the last question in this JavaScript quiz and all JavaScript
symbols had featured in earlier questions
• 74% chose “OR” with 65% correct with || and 4% with ¦¦
• not a great improvement on 70% earlier
• 25% chose && (and)
• thus virtually everyone used a logical operator
• < selected by 94%
• == correctly selected by 71% but 22% selected = which is the
assignment operator
Are the Quizzes valuable for
Learning?
• Student Feedback says yes
• Many students attempted more than once
– Quiz 2: 304 attempts by 211 students
– Quiz 4: 195 attempts by 171 students
• As indicated there is improvement as students progress
through question tries and through quizzes
• Ultimate proof in retention and throughput to further
computing courses
Student Responses – Pilot 1
• 96% of students found the quiz enjoyable
• 91% found the quiz useful
• The majority of students didn’t suggest improvements or
make any other comment, however some useful
suggestions and observations were made and one or
two errors were identified
Student Views – feedback sample
• makes it clear where to use capitals and put spaces in compound
statements
• Excellent
• ..quite short, but long enough to see if I had principles sorted
• Very useful especially with the trace tables
• It seemed to work very well
• Question 7 does not work
• Make question 3 less ambiguous
• Should include more difficult questions – stage 1 and stage 2
• Questions about repetition and selection could be less ambiguous
if construct – Q2 cont
if constructs – Q3
•75% of responses correct
at 1st attempt
• 3% wrong after 3rd
attempt.
The majority of the
errors were at the
boundary, as here,
though several
students reversed
After a 2nd attempt, the correct answers were retained, as shown, for
the final attempt.
if constructs – Q6
On 1st attempt the number of wrong answers is given along with a
reminder of the OR (||) operator's effect. The 2nd attempt has feedback as
above and the 3rd attempt starts with all the correct responses retained.
A Vision for Student
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