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<Londenp> Hi. Question for someone who knows the Parser functions: Is there a way how I can find out with parser language if a certain article is in a category. 
Something like if AAA is in CAT:BBB then display a certain image?
<Splarka> probably need DPL for that (depending on what you wanna do exactly)
<Londenp> In fact it is for Wikibooks
<Londenp> We have categorized the books in fases 0 to 4
<Splarka> or in JS or CSS
<Londenp> I would like to show on the front page a bookname together with a symbol for the development states
<Londenp> I couldn't find a solution with magic words and a parser
<Splarka> Londenp: well, what categorizes it? a template? or the [[category]] added directly?
<Londenp> with a template
<Splarka> so, like {{devstate|3}} ?
<Splarka> you can use the template to categorize, and generate the image
<Splarka> say you had {{devstate|3}} for example
<Splarka> [[Category:Development state {{{1|0}}}]]
<Splarka> {{#switch:{{{1|none}}}
<Londenp> OK
<Duesentrieb> Splarka: but he wants the image not on the page that is categorized, but on a pages that links to the page that is categorized
<Splarka> |0=[[Image:Devstate_0.png|40px]]
<Splarka> |1=[[Image:Devstate_1.png|40px]]
<Splarka> etc
<Splarka> really? hmmmm'
<Londenp> Duesentrieb exactly
<Splarka> DPL or javascript
<Duesentrieb> don't know if something like that any case, it would be tricky with parser cache
<Splarka> javascript could do it in a quick query to the API
<Londenp> We have Dynamicpagelist installed
<Duesentrieb> disabling it is the obvious solution, that would suck for the front page though
<Splarka> (but on the front page that would be messy)
<Splarka> DPL should be able to do it then
<Londenp> not DPL alas
<Splarka> which wikibooks?
<Londenp> nl
<Londenp> Rereading the remark from Duesentrieb it is still a little different
<Splarka> useful how it doesn't say what version of dpl it has
* Splarka grumbles
<Londenp> it is the old old one
<Londenp> This one
<Splarka> drat, don't think you can do what you want with it then
<Londenp> That is what I thought
<Londenp> It is very useful though, but the most modern version of DPL is much better
<Londenp> but I was not allowed to let that be installed on
<Londenp> might try again thoug on bugzilla
<Londenp> So my idea is this {{template|bookname}} for each book
<Londenp> this will show a link to the book and display a image for the status of development of this book
<Londenp> this will automatically be updated if the status is changed
<Splarka> only way I can think of is the API, but on the mainpage that would be a lot of queries to it (and it isn't cached)
<Splarka> or a custom extension
<Londenp> The information for the status of the book is with a DPL-thing in a hidden category and the template would look in which 
hidden category for the status it is and then display the according image
<Londenp> OK too bad then
<Splarka> OR.. you could create subpages for each book, that indicate the status
<Splarka> such as {{Somebook/status 1}}
<Splarka> and use #ifexist
<Splarka> but that'd be... messy
<Londenp> That is a good idea
<Londenp> Sparkla Thanks I will try that then
<Splarka> uhoh
<Splarka> don't you hate it when someone is threatening to jump off a bridge, and you say "go for it" sarcastically.. and then they do...
<Splarka> Londenp: you could also create one subpage, like [[Bookname/status]]
<Londenp> You might give me another choice :-=)
<Splarka> and have that /status contain the image that you want to transclude
<Splarka> and then always transclude [[{{{1}}}/status]] if it exists
<Splarka> that way you don't have to create and delete pages continually
<Londenp> yep
<Splarka> {{#ifexist:{{{1}}}/status|{{{{{1}}}/status}}|[[Image:Nostatus.gif]]}}
<Londenp> In fact we have something like an Infobox with the book that contains all information already
* Splarka nods
<Londenp> I just don't know how to substract that
<Splarka> heh
<Splarka> well, then...
<Splarka> what if /status only contained the number
<Splarka> 0 to 4
<Splarka> and on the infobox:
<Splarka> [[Category:Development status {{{{{FULLPAGENAME}}/status}}]]
<Splarka> and on the main page:
<Splarka> {{#ifexist:{{{1}}}/status|[[Image:Status_{{{{{1}}}/status}}.gif]]|[[Image:Nostatus.gif]]}}
<Splarka> then you just update that /status page, and both the main page and the infobox are changed
<Londenp> OK, looks good
<Londenp> but I need a little time to understand this (not being educated)
* Splarka nods
<Londenp> Sparkla thanks, I am going to study your proposals and work it out. When I have some more questions I will return.
<Splarka> thanks for the warning ^_^

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Citaten Papier[bewerken]

  • The paper burns, but the words fly away - Ben Joseph Akiba
  • What the world really needs is more love and less paper work - Pearl Bailey
  • Anything on paper is obsolete - Craig Bruce
  • This paper will no doubt be found interesting by those who take an interest in it - John Dalton
  • When the weight of the paper equals the weight of the airplane, only then you can go flying - Donald Douglas
  • When you sell a man a book you don't sell him just 12 ounces of paper and ink and glue-you sell him a whole new life - Christopher Morley
  • A specification that will not fit on one page of 8.5x11 inch paper cannot be understood - Mark Ardis
  • A child's life is like a piece of paper on which every person leaves a mark - Chinese Proverb

Version Release Date Comments
1.7 13/03/2007 Ignore non-list lines when generating blacklist
1.6 15/01/2007 Support multiple-language translations
1.5 16/12/2006 Don't block all usernames when the blacklist contains blank lines
Use Unicode-friendly regular expressions
Don't show errors when the blacklist contains only comments
(above fixes from Brion Vibber)
1.4 19/06/2006 Fix fatal error
1.3 06/07/2006 Cache blacklist in memcached or similar, if available
1.2 25/04/2006 Performance rewrite
Allow users with the uboverride permission to pass the blacklist
1.1 08/03/2006 Make compatible with MediaWiki 1.5.8
Allow commenting out lines with #
1.0 09/01/2006 Initial version

Boekenplank en boekenkast[bewerken]


[[{{{Vorighoofdstuk}}}|Vorig hoofdstuk]] Crystal Clear action 2leftarrow.png
[[{{{Vorigepagina}}}|Vorige pagina]] Crystal Clear action 1leftarrow.png
[[{{{Volgendepagina}}}|Volgende pagina]] Crystal Clear action player play.png
[[{{{Volgend hoofdstuk}}}|Volgend hoofdstuk]] Crystal Clear action 2rightarrow.png
[[{{{Inhoudsopgave}}}|Inhoudsopgave]] Crystal Clear action playlist.png
[[{{{boek}}}|Papier]] Crystal Clear action 1uparrow.png


visible text godsdienstige beweging in de 16e eeuw onder leiding van Maarten Luther en Johannes Calvijn


Normal multiplication turns this into:

The expectation of theta is exactly theta, so you can write it like that:

Add two parameters: one with a negative sign and the other with a positive sign (the sum of both is 0, but you can use that in additional calculations)

Now the second part is the usual (a-b)^2, which can be written as a^2 - 2ab + b^2. You just work the other way around.

And the first part is the variance of theta-hat and the second part is the bias. This can be written as:

Now when theta-hat is unbiassed this means that the expectation of theta-hat is equal to theta and therefore the bias is zero.
And that means that the MSE of theta-hat is exactly the variance of theta-hat.

If we take for theta the mu and for theta-hat the X-bar, you will use the normal variance for a n-sample from a population (X) with mean μ and variance σ2 you will get:

Another calculation will be as follows: We start again with:

Now we replace theta-hat with X-bar and theta with mu and you get:

We will replace X-bar in this equation with the following:

So you get:

This you can write differently according to:


which will lead to:

We take the n in the denominator out and this becomes squarred:

which turns into:

Now the expectation is redistributed in the equation:

We know that the definition for sigma is

so you get:

This is the variance of the unbiassed sample distribution of the mean


The sum of squares to be minimized is


So we do some derivation and you get for minimization the derivative is set to 0:

Divide both sides by -2 and redistribute the summation any will get:

Take beta out and divide by Sum xi2:

And therefore the least squares estimator for β, is given by


So check if

Let us use this on the estimator in a):

Now let us fill in the proposed population model into this equation:

and you will get:

Which is:

And this can be written as:

According to biasedness equation above we can take the expectation from both sides according to:

and as

you get:

Therefore unbiasedness applies.


First we start with the equation:




Take the variance of beta-hat:

Fill in the estimator of a):

Now use the equation for Yi:

and fill that in the previous equation and you get:

Two typical properties of variance when X and Y are independent are the following:


this will be used:

Using the definition given for Variance of epsilon:


Vorig hoofdstuk

Vorige pagina

Volgende pagina

Volgend hoofdstuk





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