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Annoying statistical statements that make no sense.

43 replies

queenofthedump · 03/07/2017 14:34

Mothercare have put a thing on fb today saying 'On average 80% of babies are born with some sort of birthmark'.
AIBU or does this make no sense? It's really not an average.

OP posts:
user1471517900 · 03/07/2017 14:37

That seems fine to me. What is wrong with that statement?

queenofthedump · 03/07/2017 14:38

It's not an average. Either it's 80% or it's more or it's less.

OP posts:
VestalVirgin · 03/07/2017 14:39

Yes, either it is "on average, a newborn has one birthmark" or "80% of babies are born with a birthmark".

I get that statistics are difficult, but sometimes one just gets the impression they don't even think about whether a sentence makes sense.

(Here it looks like "average" was used in the place of "about" or "around" or "an estimated", or something)

Orlantina · 03/07/2017 14:39

80% of babies are born with a birthmark.

That's all you need to say.

People misuse averages. Don't they, Michael Gove?

soapboxqueen · 03/07/2017 14:40

Surely it just means some years it's higher, sometimes lower but if you average it out, it's about 80%.

ILookedintheWater · 03/07/2017 14:40

Are they averaging years (so 81% one year, 78% the next etc)? It makes sense if that's what they are doing otherwise YANBU.

Exactly 80% of Mumsnetters get annoyed about statistical errors approximately.

HipsterHunter · 03/07/2017 14:41

Yup. Really annoying. Advertising should have some kind of rules where they can't propagate shit stats.

VeryButchyRestingFace · 03/07/2017 14:42

If they mean in average year, 80% of babies are born with a birthmark, would that make sense?

Ie, a 10 year study was conducted on the incidence of birthmarks among newborns and it averaged out at 80% py across the 10 years.

I don't know myself. I can't do maths. Blush

queenofthedump · 03/07/2017 14:43

Ah okay, if it's an average over different years then I will give them that Grin ... I'm pleased it's not just me annoyed by it!

OP posts:
Orlantina · 03/07/2017 14:44

In the average year, roughly 80% of babies are born with a birthmark.

Just like for GCSEs - 70% of pupils achieve a pass in maths. It may vary but over the last 10 yrs, the average pass rate is 70% *

  • It might not be.
CheesesOfNazereth · 03/07/2017 14:44

Surely it just means some years it's higher, sometimes lower but if you average it out, it's about 80%

Exactly. It's not perfect language, but its easy to tell precisely what it means.

Morphene · 03/07/2017 14:44

yeah, "on average 80% of babies are born with a birthmark every year" would make sense...
as written it doesn't.

Orlantina · 03/07/2017 14:48

This always need quoting.

Q97 Chair: Secretary of State, we are moving to a novel, new section: quick fire questions and answers, inspired by the Twitter feed #askgove-5,000-plus wanting to interact with you. So we are going to go round each of us in fairly strict timing. If you could give us quick answers, that would be great.

Michael Gove: I will try my best.

Q98 Chair: One is: if "good" requires pupil performance to exceed the national average, and if all schools must be good, how is this mathematically possible?

Michael Gove: By getting better all the time.

Q99 Chair: So it is possible, is it?

Michael Gove: It is possible to get better all the time.

Q100 Chair: Were you better at literacy than numeracy, Secretary of State?

Michael Gove: I cannot remember.

VestalVirgin · 03/07/2017 14:50

And the average is pretty much superfluous there. People don't want to know exactly how unusual their baby having a birthmark is that year, people want to know whether it is normal for the baby to have a birthmark, so it would be obvious the interesting statistics would take into consideration 80% of all babies born ever since people started to count birthmarks.

Camomila · 03/07/2017 14:54

The centiles HV use I feel should come with more explanation.. lots of mums seem to worry if say their baby is under the 25% or whatever, even if they've always tracked the same one.

VestalVirgin · 03/07/2017 14:55

Were you better at literacy than numeracy, Secretary of State?

That's an interesting question.

Because I am not sure knowing what "average" means is mathematical. There's an overlap here - I would say that if you don't know what average means, that's also a problem with your grasp of language. (At least if you use it. There's lots of mathematical concepts I don't understand, but I don't use them in everyday language.)

... but perhaps this stupidity can be excused by mentioning time, too. By getting better all the time, it would be possible for all schools to have pupils exceed the average of the year before.

VestalVirgin · 03/07/2017 15:03

It would also be theoretically possible to have one school with a horribly bad performance, that drags the average down so much that all other schools easily manage to get above average, and you could say that 99% of schools are above average.

NemosKnickers · 03/07/2017 15:05

73% of statistics are made up on the spot

hackmum · 03/07/2017 15:10

Orlantina, I assume that was some kind of Yes, Minister style satire until I realised it was genuine.

It's unbelievable, isn't it? And these people are supposed to be our brightest and best. Lord help us.

ShimmeringIce · 03/07/2017 15:14

Usually on beauty products: up to 97% effective

So, that could be 0 then? They should be forced to give the minimum, not fabricate a maximum!

LurkingHusband · 03/07/2017 15:16

Because I am not sure knowing what "average" means is mathematical.

Is that mean, mode or median ?

Orlantina · 03/07/2017 16:04

The mean average is also pretty useless without knowing variation as well. And sample size. Especially sample size.

SquirrelWatcher · 03/07/2017 16:10

I hate adverts that say something is "up to 100% percent effective' at removing dirt, or dandruff, or stains. It can't be more to 100%, so....somewhere between 0% effective and fully effective then??!

howabout · 03/07/2017 16:11

Now I want to know what constitutes "some sort of birthmark" and how babies with multiple birthmarks impact the average. Also lots of birthmarks fade after birth.

Now I've just spent 5 minutes pondering something and want to know why I ought to care about this random statistic while at the same time not caring except that I have an obsessive interest in sums.

MargaretCavendish · 03/07/2017 16:12

I wonder whether the 'average' is actually across races rather than across multiple years? I think that birthmarks are much more common in some ethnicities than in others?

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