Correlation between Walsall and B'Ham scores

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z-g
Posts: 127
Joined: Sun Sep 15, 2013 2:59 pm
Location: Birmingham

Re: Correlation between Walsall and B'Ham scores

Post by z-g »

Hi all, my ds1 sat his tests 2 years ago, he scored 305(borderline) for Walsall (QMG) and was still encouraged to apply, he also took the Birmingham one and scored 213, but around beginning of April he got KEA, from the waiting list. Hope this helps. We'll be doing it all again next year, with ds2.
Bob1892
Posts: 1186
Joined: Sat Sep 14, 2013 10:14 am

Re: Correlation between Walsall and B'Ham scores

Post by Bob1892 »

Cheers for that mumbrum and z-g.
I think sacrificing the summer for prep makes a big difference but without the pressure factor!
Petitpois
Posts: 1440
Joined: Thu Jul 02, 2015 7:44 am

Re: Correlation between Walsall and B'Ham scores

Post by Petitpois »

Hi Bob / MSD if you assume test and standardisation approach are roughly comparable between Birmingham and Walsall is it fair to conclude that the main qualitative distinction is simply number chasing spots?

places in Birmingham are about 1000 vs places in Walsall roughly 500.
numbers testing in Walsall are circa 2300 vs 5300 in bham - -so while the % chances and the bell curve are similar - you still have for each percentile double the number of kids chasing 2 instead of one place.

e.g if 240 is the same as 360 in walsall - there would be say 150 at or above 360 in walsall vs 300 at the same point in Birmingham??

is that misunderstanding it??
quasimodo
Posts: 3854
Joined: Sun Sep 07, 2014 2:47 pm

Re: Correlation between Walsall and B'Ham scores

Post by quasimodo »

Bob1892 wrote:...... is there a relationship/correlation between the 2 tests?
From what I have observed from a number of childrens results who have taken both exams in the last couple of years is that in the majority of cases there is no correlation between both results.That is why high performance in one exam is no indication of the other particularly as they are marked differently.The only truism if I can use such a term is the mathematicians perform better in Walsall and the better linguists in Birmingham.
In the end, it's not the years in your life that count. It's the life in your years.

Abraham Lincoln
MSD
Posts: 1731
Joined: Tue Dec 16, 2008 6:08 pm

Re: Correlation between Walsall and B'Ham scores

Post by MSD »

We can approximately work out the rank for both areas based on a certain SD score. Let's look at a SD score of 375 for Walsall, which approximates to around 250 for KE.

Here you go..

Remember three years ago, QM boys school informed us, under data protection, that my eldest scored SD of 371 and was ranked 31st - so let's see if our formula gives us the right rank now. Also note, three years ago, there were lot less than 2300 taking the test. I think it was around 1000 children.

Standardised score of 375 - Assuming it was made up of three 125 scores it would give you a z of (125-100)/15 = 1.666 for each subject area.

This Z gives us 0.9515 which equates to approximately 4.85% scoring higher for that subject area (Try this
http://www.doe.virginia.gov/testing/tes" onclick="window.open(this.href);return false; ... _table.pdf z-table)

Assuming we had 2300 candidates sitting the Walsall test, you are looking at a rank order of around 111.

Now, if you worked this out for KE Birmingham with a standardised score of 250, you will still get 0.9515 percentile equating to approximately 4.85% scoring higher


Therefore, if KE test was taken by 5300 candidates, an SD of 250 will give you an approximate rank of 257.


Note - Do bear in mind that within the above rank order of 257 you will have boys as well as girls.
Petitpois
Posts: 1440
Joined: Thu Jul 02, 2015 7:44 am

Re: Correlation between Walsall and B'Ham scores

Post by Petitpois »

That makes complete sense and thanks. Neither me or garden pea for one second think that we rely on DD replicating the performance, on KE.

If the Walsall numbers have only increased to say 1200, then your still looking at 4-5 times the number taking the exam in Birmingham. but I suppose you have to be careful. There will be 4-5 times everybody in each category / percentile, but As Bob points out Skewed towards the linguists in Birmingham, rather than more evenly spread weighting in Walsall.

The harsh reality is beginning to sink in of the commute from Brum to Walsall, so had some helpful info from Midlands mom regarding the registration dates for the Indies - plan B whips into action.

Anyone want to do a temporary house swap for say 5 years???
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