Posts Tagged ‘Media Math’

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The Rosetta Project … like throwing a dart from Sydney to Perth and hitting the bullseye

November 28, 2014

Many commentators in Australia claimed that the Philae landing was:

This is equivalent to hitting the bullseye of a dartboard in Perth from Sydney. With a billion euro ($1.4bn) dart. While blindfolded (as the mission was powered down for almost the entire journey). ABC The Drum

Did they get the maths right?

Inner bullseye of dartboard = 12.7 mm

1 Dartboard

67P comet = 4.1 km = 4,100 m at widest point

Distance comet from earth = 520 million km

 Actually, hitting the 67P comment was more like roulette as the Rosetta mothership swung into orbit. And, as the earth and the comet are moving, the distance constantly changes, but you can watch the distance changing here.

Fabulous Graphics from the Daily Telegraph

Fabulous Graphics from the Daily Telegraph

In the Dart Throwers Universe

We will assume someone can stand on earth and throw a dart at the comet … Yes! They would need very big triceps.

3  Dart throwers universe correction

 

So the commentators aren’t even close. It would still be a feat hitting a bullseye with a dart from 160km, but that would be from Sydney to, um, Nowra on the coast. 

WHY?

Comet vs bullseye ratio mathspig

Mt Everest RAtio

4 Dart Throwers universe 3

The distance from Sydney to Perth is 4100 km. At best the commentators would be talking about throwing a dart from Brisbane to Adelaide is 2044km (below).

Brisbane to Adealide

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Now You See It. Now You don’t 2

June 25, 2013

Slot machine maths:

a lose lose date with the Pokies

slot machine reels

According to Tom Vanderbilt in The Guardian ( Slot machines: a lose lose situation, 8 JUN 2013)

Once seen as a harmless diversion, hi-tech slot machines now bring in more money than casinos – and their players become addicted three times faster than other gamblers.

 Here’s how the math works:

slot machine 2

In Australia pokie machines must return between

85%

and

90%

of money gambled.

But here is the catch. If you start out with $300 that means, surely, you’ll go home with$255 in your pocket less some for the big payouts.

WRONG! WRONG! WRONG!

According to ex-gambler Tom Cummings you’ll probably go home with

NOTHING!

In his article, Poker machine maths, (ABC, The Drum, 27 MAY 2011) it is not unusual for someone to start with $300 but put $3,000 into the  machine over 4 – 5 hours. 

Here’s the sting. According to the poker machine, $3,000 was gambled, and $300  was kept (by the slot machine). That means that the machine paid out $2,700… which is the 90 per cent return.

That’s one pension cheque gone for the week.

Warren Buffett has called

gambling in general a 

“tax on stupidity”

pickpocket

or a way of fleecing those who don’t do the maths.

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6 Pizza Pi

November 26, 2010

 

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3. The Trouble with Double

October 12, 2010

Percentages

When the Numbers involved are so SMALL the % Stated is Meaningless.

Newspapers often state that a cancer rate has doubled or increased (See pic) by 28%. Those % changes can be meaningless. For instance, double nothing is still nothing. You need the actual numbers.

 

Here is a statistic taken from Men’s Health magazine (March 2010). According to the government funded Australian Institute of Health and Welfare the actual number of Australian males who presented with melanoma in 2005 was 6,044

or   0.549  in 1,000

or 1 in 2,000.

If these numbers increase by 28% the number of Australian men presenting with melanoma will be:

 

0.703 in 1,000

or  ~ 2 in 3,000.

These numbers are not so alarming. Then again would you take any notice of statistics of a magazine that suggests a ‘sonic boom’ from a golf club is causing deafness!!!!!

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4. NO. 26 It’s Your Turn Tonight

October 12, 2010

 Probability.                                          

Independent Events are not RELATED.

Lotto draws are, as with coin flipping, Independent or UNRELATED EVENTS. Newspapers often publish the least drawn numbers prior to a major prize draw.

When on June 5 2008 the Powerball jackpot reached over $50 million, making it the biggest prize ever offered in any Australian lottery game at the time media commentators went crazy. ( See Crazy Lotto Lovers Go Bananas Again!)

The Today show on Ninesmsn website advised ‘The most-drawn Powerball numbers are 26, 22, 5, 39, 24 and 34. The least drawn numbers are 41, 32, 10, 43, 35 and 20.’ This information is worthless. These facts imply that the balls know whose turn it is and then can organise themselves so that those balls drop down the shoot. As if! The draw is random. Any number is possible.

The winning numbers, in drawn order, were: 5, 21, 11, 38 and 2, with the Powerball 33, with the final prize of $58,737,207.41

Poor old 41, 32, 10,43, 35 and 20 will have to wait for another turn!!!!!!!

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9. We’re All Gonna Die!!!!!!!

October 12, 2010

Statistics

Statistics apply to Groups not Individuals

or Why Death Rates are Over-Rated!!!

We’re All Gonna die!!!  Well, um, this statement is true. The morbidity rate for humans is still 100%. Hopefully, you will be happy, healthy and 110 years old before such statistics begin to worry you. 

Newspapers often run statistics stating that your chance of being killed by a shark is 1 in 271,257 as shown. It’s NOT.

Firstly, you know this statistic is a bit dodgy. If you do not go into the water ever you will never be eaten by a shark. You chance of being shark bait is a BIG 0.

Secondly, these statistics apply to groups not to the individual. In every 271,257 Australians 1 MIGHT be eaten by a shark. In 251, 257 surfers the numbers eaten by a shark would be MUCH greater. 

Finally, these numbers still seem high. What?  77 people are killed by sharks in Australia annually. NO. These are statistics over a lifetime. 80 years, say. Less than 1 Aussie a year is killed by sharks on average but just because one surfer has died you cannot say ‘Great! The sharks have reached their annual quota I can go back in the water.’

Statistics can NEVER tell you WHAT might happen to you!

It’s a GROUP THING. All you can learn from these statistics are the  exit-the-earth probabilities for Australians that, mostly, we don’t get to choose.