[Year 12 SofDev] SD Exam - Question 4

Wed Nov 17 15:23:19 EST 2010

Maybe kids interpreted it that way because they didn't give the question
sufficient consideration. I bet stronger kids were thinking "WTF is
*this*about?"  I feel sorry for them.

But the question specifically demands an answer based on *effectiveness*,
not efficiency.

And anyway, if all 4 tests were run (as the question says), *there is no
difference in either efficiency either* - there was no mention of 'short
circuiting' of later tests based on the results of earlier tests.

In fact the question stressed that "the program has to provide *as much
information as possible* about what is wrong" which was why the four tests
were demanded in the first place.

To earn marks, if kids have to rewrite key words of a question, and insert
unspoken assumptions that contradict the explicit wording of the question,
we're all in *deep* trouble!

On 17 November 2010 14:54, Laurie Savage
<savage.john.l at edumail.vic.gov.au>wrote:

>  That’s how my students read it and I agree.
>
>
>
> Laurie
>
>
>
> *From:* sofdev-bounces at edulists.com.au [mailto:
> sofdev-bounces at edulists.com.au] *On Behalf Of *Andrew Shortell
> *Sent:* Wednesday, 17 November 2010 1:45 PM
>
> *To:* Year 12 Software Development Teachers' Mailing List
> *Subject:* Re: [Year 12 SofDev] SD Exam - Question 4
>
>
>
> Null  - if there is nothing then what is the point in proceeding further
> Type – if there is other than numbers then no point in doing any other
> checks
> Length – no point in checking the database if there is incorrect number of
> digits
> Existence – checking the database is a significant step which goes outside
> of the current program to an external source
>
> I have not yet seen the exam.. It is not offered here but as a teacher of
> IS/SoD for a few years and lectured to 3rd year programmers this is how I
> would approach it.
>
> Effectiveness in terms of why go to the next step when it has failed a
> step...
> It would be pretty silly to put it in the reverse order would n’t it...
> Check against the database before you even know if anything has been
> entered? Etc
>
> Andrew
>
>
> --
> Andrew Shortell
> (soon to leave Wallan SC)
>
>
>
> On 17/11/10 1:10 PM, "Mark KELLY" <kel at mckinnonsc.vic.edu.au> wrote:
>
> Hi all.  I've started getting a bee in my bonnet (or a terrier in my
> trousers) about Section C, Q4.
>
> *Percy is writing the program specification. For the section dealing with
> entry of the Medicare number he writes
>
> If the user makes a mistake entering the Medicare number, the program has
> to provide as much information as possible about what is wrong. Therefore
> include these validation tests.
> Length - to make sure that the correct number of characters has been
> entered
> Existence - to make sure that the number entered exists on Medicare's
> database
> Null - to make sure something has been entered
> Type - to make sure that only numeric characters have been entered
> Note: These tests must be performed in the most effective order.
>
> a. Place these validation tests in the most effective order. 1 mark
>
> Then students have to give 3 reasons why it's the most effective way of
> doing those tests. (3 marks)
>
> *
> Hmm. What is "effective" about the order? It must relate to *how well* it
> does the job of finding invalid numbers.
>
> But if *all 4 tests* are going to be conducted, any order of the 4 tests
> will yield *exactly the same* results.
>
> It might be different if we wanted to find invalid numbers *soonest,* or
> with the *minimum number of tests*, but they are *efficiency* criteria,
> not effectiveness.
>
> I'm seriously starting to believe that this is a Bull Mastiff of a
> question... All orders must be equally effective.
>
> I can usually work out what the examiners were *probably* trying to get
> at, but this one has me completely baffled (like multichoice Q3 on the ITA
> paper).
> I have no idea whatsoever of what knowledge the examiners are hoping I will
> show.
>
> So, can anyone please tell me:
>
> 1. how one order can be *more effective* than another.
> 2. what order is most effective, and why the *reverse order* would be less
> effective!
>
> Growl.
>
> Mark
>
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-- 
Mark Kelly
Manager Information Systems
Reporting Manager
IT Learning Area Manager

McKinnon Secondary College
McKinnon Rd McKinnon 3204
Victoria, Australia
Direct line / Voicemail: +613 8520 9085
Fax +613 9578 9253
kel at mckinnonsc.vic.edu.au

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