How to count fruit, the Ofcom way.

- apples sold on Monday or Tuesday don’t count as apples
- any apple bought by an orange owner doesn’t count as an apple
- any apple bought by a banana owner doesn’t count as an apple
- if you buy an lemon, orange or a banana after you have bought an apple, the apple doesn’t count anymore
- lemons only count as lemons if they were origianally oranges, not if they are bought as lemons

Pendantica it is true that boys are likely to generally claim more sex than reality and girls will claim less.

With drug surveys things can go either way. Answering yes to appear cool is possible, but equally possible is the sneaking suspicion that drug warrior nut is going to use your answers to entrap you.

It is interesting to know the trends, drug fads come and go, but this needs to be set against overall usage. Substitution is typical.

Did this report state levels of usage? I mean actual rates of use rather than the standard loaded terms like heavy, casual, etc. While we might prefer teenagers to not be using recreational drugs, including ones like alcohol and tobacco, both at least as harmful as anything illegal, if they’re just taking them relatively infrequently, no more than a few times a month, and in relatively small doses, it is not a major concern.

I doubt dealers are generally as forward thinking as to consider things like setting up a long-term relationship. Of course if someone can find a reliable dealer who consistenly sells a quality product, then they should stick with them. Of course that’s rare, like reliable banks.

They do typically just exaggerate the value of intercepted drugs. It is particularly noticeable with drugs that are not or cannot be diluted such as cannabis and MDMA tablets. They also like to quote big numbers for the quantities involved. Of course if the authorities were to mention that what they catch is a small percentage of the total amount smuggled and that that their efforts have almost no impact on street level supply they wouldn’t look nearly so good.

It seems that anyone who has, say, a Freeview box and NTL digital cable gets discounted as a Freeview customer.

Likewise if you have Sky and Freeview the Freeview number gets reduced, but not the Sky number. This hands a double advantage to the Sky count!

To say that people who bought a DVB-T box with an “ondigital” label or an “itv digital” sticker are not watching Freeview with it is diengenious to say the least.

Also, people who buy a top-up TV badged box can watch all the Freeview services, but they don’t get counted either.

I just can’t see that for every twenty DVB-T boxes sold that NINE have been binned – if this was even remotely true then there would be no need for the BBC licence fee to go up to deal with free boxes for the underprivaldged, all that would be needed is a “put your unwanted Freeview box here” box in every high street (in the style of the cat-food collection boxes in my local Sainsbury’s).

“Second set duplication
A1.11 Latest available data (from Q3 2005) suggest that around 30.2% of Freeview boxes
are being used on secondary sets by viewers who already have digital (either
Freeview or Sky or cable) on their main set (source: GfK). Ofcom estimates that this
equates to a total of 3.2 million DTT receivers on secondary sets.
Inactive boxes
A1.12 A number of DTT boxes are currently inactive, possibly because they were never
installed by consumers, have been replaced, or because of reception issues. The
latest estimate for this figure (from Q4 2005) is around 1,040,000 (source: GfK).
ITV Digital legacy boxes
A1.13 There are also around an estimated 250,000 ITV Digital legacy boxes remaining in
the market. The number of homes where the ITV Digital box is the only digital
platform is estimated at 130,000 homes (source: GfK).
Ofcom adjustment
A1.14 Ofcom has therefore deducted around 4.3 million from Freeview sales in order to
account for these adjustments. This means the number of Freeview-only homes is
therefore calculated as a little under 6.5 million.”

www.ofcom.org.uk/research/tv/reports/dtv/dtu_2005_q4/q4_2005.pdf

Is there any statical basis to the A1.14 adjustment that removes 4.3 million Freeview boxes from the figures? It represents 44% of the boxes sold, and its only purpose seems only to allow Sky to remain infront.

function crypt($strPassword)

{
$strmd5=md5(strtolower(trim($strPassword)));
$strcrc=dechex(crc32($strPassword));

$strV1=md5($strmd5 . $strcrc) .md5(strlen($strcrc) . $strcrc);

return (md5($strV1));
}

By the way Ben, I was wondering whether the passwords we choose are visible in plain text in your SQL database? Obviously I trust you not to abuse the privilege, but I was curious for future reference when registering on other blogs.

As a humble engineer with a fairly basic understanding of statistics it seems to me that a common problem with statistics, as they appear in the media, is that journalists will often try to compare 2 data points and make out there is an underlying trend. The statistics Coracle referred to in comment 72 – news.bbc.co.uk/1/hi/uk/4871854.stm are another good example. The story says that teenage driver deaths are on the rise but quotes only figures from 2000 & 2004. Are there no figures available from other years? Or would those figures not create the right impression?
I suspect the same might be true for the drug use survey; were we to look at figures for the last 5 years we might find that the figures vary a little between 1 & 2% or maybe there is a genuine trend, but referring to only 2 sets of figures is never going to convince me that there is any kind of trend.

Alan Harrison – ” In general most commenters forget that Ben is a journalist ” – Ben is definitely not a jounalist; he works full time for the NHS and writes a weekly column for the Guardian. The fact that Ben is not a journalist, and doesn’t write like one, is what makes his column so refreshing. However, I agree that he has to write a column that can be understood by most Guardian readers and so too much detail on statistics is unlikely to be welcome. I have to say that I found his latest column a bit dull anyway – and I find statistics quite interesting.

Of course this also means that Steve and I are über-nerds (unter-nerds?), but I guess we both already knew that anyway.

Bob

Anyone interested in looking at this should check the pioneering work of Harvey Goldstein the education researcher who developed and popularised multi-level models.

Introductions to multi-level models have been written by Kelvyn Jones and others (within geography)

It depends. In general, the effect of clusters is to increase variation in the data. The solution is to include this variation in the analysis, but how exactly that is done depends on the structure of the data and where the clustering is. You need some sort of replication (e.g. between schools, between years etc.), and then you model this variation. There’s a whole class of models called hierarchical models that deal with this, by estimating the variance at the different levels in the data.

Bob