OnPoint: Re: Education
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Ziiiiiiiiing

Ouch.

The link at the top of the article is stuffed ;)
Why does the "Goodness of Fit" explanation talk about "R^2" but the table above it talks about the "r value"  or are these unrelated?

Luis,
In a simple linear regression (like in the pictures) R^2 is the proportion of the observed variability in the yaxis which is explained by the observations in the xaxis. In that setting R^2 is also the squared correlation (r) which measures the association between the variables x and y.

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Didn't they have a system at high decile schools like Auckland Grammar whereby if you were in the rugby team or whatever, the teachers signed you off as passing university entrance without actually needing to do any exams?

I'm not convinced that R^2 is a useful measure of goodness of fit in this case, especially with the ridiculously prescriptive interpretations given by this textbook.
The real problem here is confounding variables.

Are the values clustered to the bottom left the special schools?

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Brilliant article! Thanks!!!

Sacha, in reply to
apparently

Bart Janssen, in reply to
Why does the "Goodness of Fit" explanation talk about "R^2" but the table above it talks about the "r value"  or are these unrelated?
I'm pretty sure "r value" is slang for R^2. They are the same thing.

Bart Janssen, in reply to
Are the values clustered to the bottom left the special schools?
They probably are but it's worth looking, outliers are often very informative.

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A shot to the heart, if the Harold actually had a heart...

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Are the values clustered to the bottom left the special schools?
Yep. I have no idea why they're in the data set.
Most of the other low scoring, high ratio schools are remote rural low decile schools with, like one teacher and eleven students. Amazingly they aren't delivering a comprehensive education.

It's also worth noting that the value on the X axis is probably real.
But the value on the y axis is probably a lot of shit.
Not really much point in plotting shit vs real.

Graeme Edgeler, in reply to
Most of the other low scoring, high ratio schools are remote rural low decile schools with, like one teacher and eleven students. Amazingly they aren't delivering a comprehensive education.
National Standards don't address a comprehensive education.

Keith Ng, in reply to
The real problem here is confounding variables.
Agreed.

Keith Ng, in reply to
Are the values clustered to the bottom left the special schools?
Yes. See http://dimpost.wordpress.com/2012/09/23/wellbelowstandardinanalysis/

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Is this "data" file available somewhere for constructing other spurious correlations?

Nathaniel Wilson, in reply to
I'm pretty sure "r value" is slang for R^2. They are the same thing
They're really not. Very roughly speaking, r gives you an indication of whether the two variables have a relationship, r^2 provides an indication of how much variance in the data can be explained. r^2 =1 means the line explains all the variance, r^2 of 0.074 means the line explains 7.4 % of the variance; sweet FA in other words. You could probably plot number of cars per household or number of badminton players per school on the xaxis and get just as good results.

I can't even tell if the HoS is trying to make a metajoke by channelling Helen Lovejoy from the Simpsons with their editorial Won't someone please think of the children?.
Still, it states:
In fact, buried within the national standards dross is valuable information about how boys are struggling, the decline in writing skills, and Pacific children getting lost at the back of the classroom.
If the idealogues on either side would stop to think, they might realise it is better to intelligently discuss pupils' results than try to hide them.OK, even if we, for the sake of argument, accept that the raw data is ‘correct’, how would the HoS (or any of the main papers) manage to sift through the ‘dross’ to find this ‘valuable information’?
As shown by Keith above, this is highschool statistics and the National Standards shock: Big classes work article completely fails at even this basic level.
I don't expect everyone to have a working knowledge of statistics, but if you actually attempt to do some analysis and then publish your 'findings', I would expect the analysis to be given at least a 5minute check by someone with that basic knowledge.

Ray Gilbert, in reply to
A shot to the heart, if the Harold actually had a heart...
Wouldn't that be an arrow to through the eye?

Russell Brown, in reply to
National Standards don’t address a comprehensive education.
No – and they don’t measure performance against the primary school curriculum either. But the level of resourcing available at tiny rural schools is extremely likely to have an impact on national standards scores. A singleteacher country school will not, for example, have a reading recovery specialist on staff.
BTW, it seems to me that the HoS story isn't actually based on class size as such  that information is not collected by the Ministry of Education  but on pupilteacher ratios across schools. Which isn't the same thing.

Bart Janssen, in reply to
r gives you an indication of whether the two variables have a relationship
But in statistics a relationship is defined by the probability of the occurance of that relationship by pure chance. A relationship has no meaning unless there is a probability. While we are probably wrong to do so we do tend to use "r value" when we are referring to the probability that the relationship could have occured by chance. But we are mere molecular biologists in this lab :).

Does anyone know why the Funding per Student figures vary so much between schools of the same decile ?

Bart Janssen, in reply to
BTW, it seems to me that the HoS story isn’t actually based on class size as such – that information is not collected by the Ministry of Education – but on pupilteacher ratios across schools. Which isn’t the same thing.
So not only is the y axis full of shit but so is the x axis?!?!?
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