Pass Mark Confusion

yoyo123 · Post by **yoyo123** » Wed Oct 21, 2009 1:32 pm

The scores are standardised to fit into a Normal or Bell Curve

This a normal curve from IBM projects, but is quite good at explaining, the scores for passing would be in the 'very' or 'extremely' ranges on the right hand side.

yuckymummy · Post by **yuckymummy** » Wed Oct 21, 2009 1:41 pm

Have just spoken to Judd who confirm 140 is not 100%, but around 75% and over.

Then spoke to someone else at KCC (head of department) who confirms this but cannot confirm what the percentage as it changes year to year.

Now just have to persuade my OCC head teacher that 140 is not 100% and therefore my DS score was considerably lower than we all expected and there should have been head teacher referral.

marymay · Post by **marymay** » Wed Oct 21, 2009 2:08 pm

I have a feeling that 140 is supposed to represent three standard deviations from the mean; in other words the top 1% of the total population of children in the county. A score of 120 would represent one standard deviations from the mean - the top 25% of the population and so deemed suitable for grammar education.

Any statisticians/mathmaticians out there. If the 11+ is a fair test what are the chances of a class of 23 children having seven children (30%) scoring 140 in the test, as mentioned in another post?

dadofkent · Post by **dadofkent** » Wed Oct 21, 2009 2:13 pm

yuckymummy wrote: Then spoke to someone else at KCC (head of department) who confirms this but cannot confirm what the percentage as it changes year to year.

The actual percentage raw score also deopends on the age of the child.

yoyo123 · Post by **yoyo123** » Wed Oct 21, 2009 2:30 pm

marymay wrote:I have a feeling that 140 is supposed to represent three standard deviations from the mean; in other words the top 1% of the total population of children in the county. A score of 120 would represent one standard deviations from the mean - the top 25% of the population and so deemed suitable for grammar education.

yes you're right about the Standard deviations, in the diagram above the sigma stands for Stdandard Deviation.

rachel'smum · Post by **rachel'smum** » Thu Oct 22, 2009 11:14 am

tired_dad_2008 wrote:[
KCC do give out raw scores so you can tell what the 140 equivalent is in each subject.

How do we get these - can we email KCC does anyone know?

Twinkle · Post by **Twinkle** » Thu Oct 22, 2009 12:40 pm

I emailed on Tuesday, but so far no response. I'm assuming that the admissions department is very busy at the moment. I will probably ring if I don't hear in the next few days.

medwaymum · Post by **medwaymum** » Thu Oct 22, 2009 12:57 pm

Same here!

WP · Post by WP » Thu Oct 22, 2009 3:00 pm

marymay wrote:I have a feeling that 140 is supposed to represent three standard deviations from the mean; in other words the top 1% of the total population of children in the county. A score of 120 would represent one standard deviations from the mean - the top 25% of the population and so deemed suitable for grammar education.

The usual convention is a standard deviation of 15, so 140 would be just under 3 standard deviations, i.e. the top 0.4%.

marymay wrote:Any statisticians/mathematicians out there. If the 11+ is a fair test what are the chances of a class of 23 children having seven children (30%) scoring 140 in the test, as mentioned in another post?

If the children were randomly selected, roughly equal to the chances of winning the lottery 3 weeks in a row. Correction: about 3 in a trillion. That's assuming scores have an average of 100 and a standard deviation of 15, which might not be the case. For example Bucks standardize to an average of 111 and a standard deviation that seems to be a bit more than 15.

marymay · Post by **marymay** » Thu Oct 22, 2009 3:27 pm

Thanks WP, very interesting.