# Boards

## I have a maths issue.

A colleague was pointing out to me that if you double, say 3, to 6, it has gone up by 100%.

But if you take 6 down to 3, it's fallen by 50%.

I didn't have a decent answer for this, but she was pointing out that as jounrnalists reporting statistics we can use this to our malicious advantage, which worries me...

## people are inherently rubbish with statistics.

You've read bad science haven't you, cause I think you were talking about it one day?

## I read the weekly columns, yeah.

I'm always sceptical of stats, but in this instance, it just feels like there's something logically wrong - you're taking the same figures, just in different directions, yet the description, in percentage terms, is wildly different. SOMETHING MUST BE DONE.

## its ratio's.

and 3 is not 6 so obviously they will be different ratio's.

## I love this:

"3 is not 6"

## :D?

## Ratio's what? WHAT I'S IT? TELL U'S!

## its apostrophe's.

apostrophe's, I tell's yer's.

## yes. you should always question statistics:most people don't

understand them at all and often newspapers either use this to exaggerate their points/give weight to their arguments, or get them wrong because they don't understand them either.

This is good:

http://news.bbc.co.uk/1/hi/programmes/more_or_less/default.stm

## it's not what you say, its how you say it.

innit?

## That's what gets results

## I really don't see why you would have an issue with this

## Say we get some police figures about crime on trains.

Last year there were ten robberies and five sexual assualts. This year, five robberies and ten sexual assaults.

The story can say "There has a massive 100 per cent rise in sexual assualts, whereas burglaries has only fallen by 50 per cent".

But the numbers of crimes haven't changed.

## its like the equivalent of reordering the words you use in a sentence.

just because they are the same words don't mean they mean the same thing.

## Nothing you wrote suggested the number of crimes changed.

But you're right that statistics can be used to mislead

## If something has gone up by 100%, and something else has fallen by 50%,

you could easily infer a net rise of 50%.

I'm not really arguing anything, except that statistics are worrying.

## Fair enough

Without figures statistics are meaningless

## Statistics is just a way of analyzing figures though

raw data is less useful than analyzed data surely?

## only if the analyzed data tells you what analysis has been carried out

and that that analysis was valid

## i dunno what you're talking about.

but i'm giving everything for this thread. 110%.

## I have a meths issue.

^ This is a thread waiting to happen.

## I'm only giving 50% of everything

so, I'm giving 55%

## Lies, damn lies and statistics.

It's made worse when so many of the articles are written by humanities graduates who don’t understand statistics, and a general public who still think it’s cool to say, “I’m rubbish with maths; used to hate it at school.”

## you normally have to take a statistics course for any of the social sciences i believe.

## Probably more a general public who are rubbish at maths

## This made me remember this doozy of a story:

http://menmedia.co.uk/manchestereveningnews/news/s/1022757_cool_cash_card_confusion?page_size=50

## :)

"They fobbed me off with some story that -6 is higher - not lower - than -8 but I'm not having it."

Get me the Royal Society! I have a complaint about science!

## Proof that it's a tax on the stupid?

See also: http://www.guardian.co.uk/lifeandstyle/2010/may/22/threw-hundred-thousand-pounds-in-bin

Gotta feel for the guy. Kinda. Maybe. Oh, okay, he's a doofus.

## i think anyone who understands how maths works

can understand how this can happen

## Yes.

Unfortunately, vast vast swathes of the population will be confused by this very very simple bit of maths*. It's frequently abused by journalists looking for meaty figures.

*I was temping at an Ofsted Early Years** office, and they were due to take a basic maths competency test. This exact issue arose. Most people couldn't get their heads around of something being "more than 100%" or the crux of the calculation being to derive what 1% represented at a particular point in time and then multiply accordingly.

**Not especially relevant, but it gives you a flavour of the folk involved.

Verdict: Worrying for the country if this is what's keeping it going. Not worrying for my employment prospects if this is what I'm up against.

## it's amazing the amount of people i knew through school

who said that maths is a waste of time

they're fucking idiots, and probably sitting in a pile of their own filth

maths solves everything

## re: "maths is a waste of time"

It's not even that you need to remember the maths that you do. Much of the stuff at GCSE probably /is/ left unused for most folk. It's the ability to calmly analyse a problem, understand what's going on, and then do some really simple stuff to solve it.

So many people aren't able to do even that. Maybe it's a confidence thing?

## That's nothing

The probability that a woman of age 40 has breast cancer is about 1 percent. If she has breast cancer, the probability that she tests positive on a screening mammogram is 90 percent. If she does not have breast cancer, the probability that she nevertheless tests positive is 9 percent. What are the chances that a woman who tests positive actually has breast cancer? Answer: 10 percent.

## I wanna say 50%...

What's the answer?