April 14, 2014

Stat of the Week Winner: April 5 – 11 2014

Thanks to James Green for nominating this fascinating statistic (if true):

“A 1 per cent improvement in broadband connectivity is estimated to cause a drop of 200 million litres a year in national fuel demand”

The NZ Herald quoted this (without attribution) but Thomas Lumley tracked down the source of the statistic to a report by Z Energy. The report contains no further details on the statistic.

James wrote:

“Would be fascinating if true, but without them revealing an actual source, seems difficult and barely credible to firmly link these two.”

Congratulations James for being our Stat of the Week Winner!

Stat of the Week Competition: April 12 – 18 2014

Each week, we would like to invite readers of Stats Chat to submit nominations for our Stat of the Week competition and be in with the chance to win an iTunes voucher.

Here’s how it works:

  • Anyone may add a comment on this post to nominate their Stat of the Week candidate before midday Friday April 18 2014.
  • Statistics can be bad, exemplary or fascinating.
  • The statistic must be in the NZ media during the period of April 12 – 18 2014 inclusive.
  • Quote the statistic, when and where it was published and tell us why it should be our Stat of the Week.

Next Monday at midday we’ll announce the winner of this week’s Stat of the Week competition, and start a new one.

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April 13, 2014

Housing affordability map

Saeid Adli and Alex Raichev have made interactive maps of Auckland and Wellington that try to combine the cost of housing (rent) and commuting, and present it as a fraction of income.  You can select income, house size, mode of transport, how often you commute, etc.

They also provide an explanation of how they do the calculations, and all the code and data.

Briefly

April 11, 2014

Past performance no guarantee of future results

From the ACC

Julius Caesar was warned to beware the ‘Ides of March’. And perhaps Kiwis should take extra caution this Sunday.

That’s because April the 13th last year was the day on which the highest number of injuries happened during 2013.

Of course, April 13th wasn’t a Sunday last year. ACC helpfully give us the top five days last year for injuries

  • 13 April – 8,067 claims
  • 6 April – 8,024 claims
  • 11 May – 7,988 claims
  • 18 May – 7,757 claims
  • 8 June – 7,732 claims.

What do all these days have in common? Well, let’s just say that the ACC warning for Sunday April 13 may be a bit late.

 

The favourite never wins?

From Deadspin, an analysis of accuracy in 11 million tournament predictions (‘brackets’) for the US college basketball competition, and 53 predictions by experts

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Stephen Pettigrew’s analysis shows the experts average more points than the general public (651681 vs 604.4). What he doesn’t point out explicitly is that picking the favourites, which corresponds to the big spike at 680 points, does rather better than the average expert.

 

April 10, 2014

Frittering away

Q: Did you see that “some generation Y foodies are spending up to $600 a week on gourmet produce such as seafood, cheeses, olives and cured hams.”

A: In the Herald? Yes.

Q: Is it true?

A: Slightly.

Q: Who are these people?

A: Well, for a start, they’re Australians

Q: Oh. How many is “some”

A: At least one.

Q: No, seriously, how many?

A: 1% of a the 18-34 subset of a sample of ‘over’ 1000. Here’s the full report

Q: How many is that?

A: Maybe three in the sample?

Q: Three people or three households?

A: A good question. They don’t say, though the average weekly food expenditure in their sample looks reasonably close to the national household average that they cite.

Q: How were the people sampled?

A: They don’t say.

Q: How many were Generation Y?

A: They don’t say

Q: How did they even define ‘gourmet food’? Or don’t they say that either?

A: Sadly, no.

Q: This report doesn’t seem to follow the code of practice you blogged about recently, does it?

A: That was just for political polls, and anyway this report is Australian.

Q: Is there anything else you want to complain about in the report?

A: If  you call it an “Inaugural” report you really can’t use it to conclude “Australians are becoming a more food savvy nation”.

 

April 9, 2014

NRL Predictions for Round 6

Team Ratings for Round 6

The basic method is described on my Department home page. I have made some changes to the methodology this year, including shrinking the ratings between seasons.

Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Current Rating Rating at Season Start Difference
Roosters 9.12 12.35 -3.20
Bulldogs 6.88 2.46 4.40
Rabbitohs 5.14 5.82 -0.70
Sea Eagles 5.13 9.10 -4.00
Cowboys 4.48 6.01 -1.50
Storm 3.21 7.64 -4.40
Knights 1.69 5.23 -3.50
Titans 0.61 1.45 -0.80
Panthers -1.66 -2.48 0.80
Sharks -1.93 2.32 -4.30
Broncos -2.18 -4.69 2.50
Raiders -4.29 -8.99 4.70
Warriors -5.04 -0.72 -4.30
Wests Tigers -5.72 -11.26 5.50
Dragons -6.44 -7.57 1.10
Eels -10.77 -18.45 7.70

 

Performance So Far

So far there have been 40 matches played, 18 of which were correctly predicted, a success rate of 45%.

Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Roosters vs. Bulldogs Apr 04 8 – 9 8.60 FALSE
2 Broncos vs. Eels Apr 04 18 – 25 17.30 FALSE
3 Sharks vs. Warriors Apr 05 37 – 6 2.80 TRUE
4 Panthers vs. Raiders Apr 05 12 – 6 7.50 TRUE
5 Dragons vs. Rabbitohs Apr 05 6 – 26 -4.20 TRUE
6 Storm vs. Titans Apr 06 26 – 28 9.20 FALSE
7 Wests Tigers vs. Sea Eagles Apr 06 34 – 18 -11.00 FALSE
8 Cowboys vs. Knights Apr 07 28 – 2 3.30 TRUE

 

Predictions for Round 6

Here are the predictions for Round 6. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Game Date Winner Prediction
1 Panthers vs. Rabbitohs Apr 11 Rabbitohs -2.30
2 Titans vs. Broncos Apr 11 Titans 7.30
3 Raiders vs. Knights Apr 12 Knights -1.50
4 Eels vs. Roosters Apr 12 Roosters -15.40
5 Wests Tigers vs. Cowboys Apr 12 Cowboys -5.70
6 Warriors vs. Bulldogs Apr 13 Bulldogs -7.40
7 Sea Eagles vs. Sharks Apr 13 Sea Eagles 11.60
8 Storm vs. Dragons Apr 14 Storm 14.10

 

Super 15 Predictions for Round 9

Team Ratings for Round 9

The basic method is described on my Department home page. I have made some changes to the methodology this year, including shrinking the ratings between seasons.

Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Current Rating Rating at Season Start Difference
Sharks 7.29 4.57 2.70
Crusaders 6.27 8.80 -2.50
Chiefs 4.65 4.38 0.30
Waratahs 4.21 1.67 2.50
Brumbies 4.00 4.12 -0.10
Bulls 3.58 4.87 -1.30
Stormers 0.66 4.38 -3.70
Hurricanes 0.51 -1.44 1.90
Reds -0.78 0.58 -1.40
Blues -1.33 -1.92 0.60
Cheetahs -3.35 0.12 -3.50
Force -3.47 -5.37 1.90
Highlanders -4.52 -4.48 -0.00
Lions -4.99 -6.93 1.90
Rebels -5.73 -6.36 0.60

 

Performance So Far

So far there have been 49 matches played, 30 of which were correctly predicted, a success rate of 61.2%.

Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Highlanders vs. Rebels Apr 04 33 – 30 5.60 TRUE
2 Brumbies vs. Blues Apr 04 26 – 9 8.20 TRUE
3 Hurricanes vs. Bulls Apr 05 25 – 20 0.30 TRUE
4 Reds vs. Force Apr 05 29 – 32 6.40 FALSE
5 Cheetahs vs. Chiefs Apr 05 43 – 43 -4.60 FALSE
6 Lions vs. Crusaders Apr 05 7 – 28 -5.40 TRUE
7 Stormers vs. Waratahs Apr 05 11 – 22 2.10 FALSE

 

Predictions for Round 9

Here are the predictions for Round 9. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Game Date Winner Prediction
1 Highlanders vs. Bulls Apr 11 Bulls -4.10
2 Reds vs. Brumbies Apr 11 Brumbies -2.30
3 Chiefs vs. Rebels Apr 12 Chiefs 14.40
4 Force vs. Waratahs Apr 12 Waratahs -5.20
5 Cheetahs vs. Crusaders Apr 12 Crusaders -5.60
6 Lions vs. Sharks Apr 12 Sharks -9.80

 

Briefly

Pie chart edition

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