Posts from September 2019 (19)

September 29, 2019

Rugby World Cup Predictions 3

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Team Ratings 3

The basic method is described on my Department home page.
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
New Zealand 27.68 27.60 0.10
England 19.27 19.78 -0.50
South Africa 17.93 18.51 -0.60
Wales 12.62 12.72 -0.10
Ireland 11.59 12.12 -0.50
Australia 9.06 8.70 0.40
France 7.02 7.11 -0.10
Scotland 3.88 5.44 -1.60
Argentina 3.52 4.15 -0.60
Japan -6.99 -7.67 0.70
Italy -7.70 -8.57 0.90
Fiji -8.61 -5.27 -3.30
Samoa -11.75 -11.89 0.10
USA -16.61 -16.38 -0.20
Georgia -17.32 -17.43 0.10
Tonga -19.00 -20.46 1.50
Uruguay -32.69 -35.67 3.00
Canada -34.06 -32.45 -1.60
Russia -35.51 -36.78 1.30
Namibia -40.57 -41.80 1.20

 

Performance So Far

So far there have been 15 matches played, 13 of which were correctly predicted, a success rate of 86.7%.
Here are the predictions for games played so far.

Game Date Score Prediction Correct
1 Japan vs. Russia Sep 20 30 – 10 35.60 TRUE
2 Australia vs. Fiji Sep 21 39 – 21 14.00 TRUE
3 France vs. Argentina Sep 21 23 – 21 3.00 TRUE
4 New Zealand vs. South Africa Sep 21 23 – 13 9.10 TRUE
5 Italy vs. Namibia Sep 22 47 – 22 33.20 TRUE
6 Ireland vs. Scotland Sep 22 27 – 3 6.70 TRUE
7 England vs. Tonga Sep 22 35 – 3 40.20 TRUE
8 Wales vs. Georgia Sep 23 43 – 14 30.10 TRUE
9 Russia vs. Samoa Sep 24 9 – 34 -23.50 TRUE
10 Fiji vs. Uruguay Sep 25 27 – 30 30.00 FALSE
11 Italy vs. Canada Sep 26 48 – 7 23.10 TRUE
12 England vs. USA Sep 26 45 – 7 35.40 TRUE
13 Argentina vs. Tonga Sep 28 28 – 12 24.00 TRUE
14 Japan vs. Ireland Sep 28 19 – 12 -16.30 FALSE
15 South Africa vs. Namibia Sep 28 57 – 3 59.50 TRUE

 

Predictions 3

Here are the updated predictions. 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 Georgia vs. Uruguay Sep 29 Georgia 15.40
2 Australia vs. Wales Sep 29 Wales -3.60
3 Scotland vs. Samoa Sep 30 Scotland 15.60
4 France vs. USA Oct 02 France 23.60
5 New Zealand vs. Canada Oct 02 New Zealand 61.70
6 Georgia vs. Fiji Oct 03 Fiji -8.70
7 Ireland vs. Russia Oct 03 Ireland 47.10
8 South Africa vs. Italy Oct 04 South Africa 25.60
9 Australia vs. Uruguay Oct 05 Australia 41.80
10 England vs. Argentina Oct 05 England 15.80
11 Japan vs. Samoa Oct 05 Japan 11.30
12 New Zealand vs. Namibia Oct 06 New Zealand 68.20
13 France vs. Tonga Oct 06 France 26.00
14 South Africa vs. Canada Oct 08 South Africa 52.00
15 Argentina vs. USA Oct 09 Argentina 20.10
16 Scotland vs. Russia Oct 09 Scotland 39.40
17 Wales vs. Fiji Oct 09 Wales 21.20
18 Australia vs. Georgia Oct 11 Australia 26.40
19 New Zealand vs. Italy Oct 12 New Zealand 35.40
20 England vs. France Oct 12 England 12.20
21 Ireland vs. Samoa Oct 12 Ireland 23.30
22 Namibia vs. Canada Oct 13 Canada -6.50
23 USA vs. Tonga Oct 13 USA 2.40
24 Wales vs. Uruguay Oct 13 Wales 45.30
25 Japan vs. Scotland Oct 13 Scotland -4.40

 

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September 24, 2019

Census news

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The first data release from the Census happened yesterday.  There are more people in New Zealand than there were in 2013.  In Auckland, 42% of the population were born overseas. There’s going to be a new electorate in the North Island somewhere. And various other facts.

I’ve been on an independent expert panel providing an external review of data quality. We also gave our first report yesterday.  It’s here.

Basically, there’s good news and bad news.

  • Stats NZ used the 2013 Census and other government data to fill in people who were missing from the 2018 Census, and to bring in their data where available
  • It worked well for general population counts.
  • It didn’t work at all for some variables, because they don’t have other data sources
  • It worked to varying degrees for other variables
  • The quality depends a lot on what you want to use it for
  • We weren’t convinced about social and cultural license for the use of administrative data

Reading the executive summary of the report is a good way to be at least slightly informed (relative to, say, Twitter), but you could also read the whole thing — we hope it’s fairly accessible.

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NRL Predictions for the Preliminary Finals

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Team Ratings for the Preliminary Finals

The basic method is described on my Department home page.
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
Storm 13.17 6.03 7.10
Roosters 11.99 8.72 3.30
Raiders 6.97 1.81 5.20
Eels 2.80 -6.17 9.00
Rabbitohs 2.76 3.89 -1.10
Sharks 1.81 3.90 -2.10
Sea Eagles 1.05 -5.61 6.70
Panthers -0.13 0.93 -1.10
Wests Tigers -0.18 -5.57 5.40
Bulldogs -2.52 -0.61 -1.90
Cowboys -3.95 0.15 -4.10
Warriors -5.17 -0.27 -4.90
Broncos -5.53 2.63 -8.20
Knights -5.92 -8.51 2.60
Dragons -6.14 0.06 -6.20
Titans -12.99 -3.36 -9.60

 

Performance So Far

So far there have been 198 matches played, 128 of which were correctly predicted, a success rate of 64.6%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Rabbitohs vs. Sea Eagles Sep 20 34 – 26 4.20 TRUE
2 Storm vs. Eels Sep 21 32 – 0 10.30 TRUE

 

Predictions for the Preliminary Finals

Here are the predictions for the Preliminary Finals. 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 Raiders vs. Rabbitohs Sep 27 Raiders 7.20
2 Roosters vs. Storm Sep 28 Roosters 1.80

 

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Mitre 10 Cup Predictions for Round 8

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Team Ratings for Round 8

The basic method is described on my Department home page.
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
Tasman 16.95 9.00 8.00
Canterbury 12.74 12.92 -0.20
Wellington 10.50 10.92 -0.40
Auckland 8.74 11.57 -2.80
Bay of Plenty 5.64 -4.82 10.50
Waikato 4.47 8.24 -3.80
North Harbour 2.28 5.30 -3.00
Hawke’s Bay -0.56 -5.69 5.10
Otago -4.16 -1.49 -2.70
Taranaki -4.51 -5.22 0.70
Counties Manukau -7.17 -1.99 -5.20
Manawatu -11.91 -11.67 -0.20
Northland -13.62 -6.23 -7.40
Southland -20.64 -22.08 1.40

 

Performance So Far

So far there have been 49 matches played, 32 of which were correctly predicted, a success rate of 65.3%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Canterbury vs. Manawatu Sep 19 29 – 32 35.60 FALSE
2 Hawke’s Bay vs. Taranaki Sep 20 35 – 17 5.70 TRUE
3 Waikato vs. Tasman Sep 21 26 – 35 -8.40 TRUE
4 Southland vs. Counties Manukau Sep 21 42 – 14 -17.70 FALSE
5 North Harbour vs. Otago Sep 21 15 – 21 14.10 FALSE
6 Auckland vs. Wellington Sep 22 15 – 34 6.90 FALSE
7 Northland vs. Bay of Plenty Sep 22 22 – 46 -13.30 TRUE

 

Predictions for Round 8

Here are the predictions for Round 8. 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 Taranaki vs. Southland Sep 26 Taranaki 20.10
2 Tasman vs. Auckland Sep 27 Tasman 12.20
3 Bay of Plenty vs. Hawke’s Bay Sep 28 Bay of Plenty 10.20
4 Wellington vs. Northland Sep 28 Wellington 28.10
5 Canterbury vs. Counties Manukau Sep 28 Canterbury 23.90
6 Otago vs. Waikato Sep 29 Waikato -4.60
7 Manawatu vs. North Harbour Sep 29 North Harbour -10.20

 

Rugby World Cup Predictions 2

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I was hoping to be able to release predictions in batches of 8 matches, but some matches which could be predicted already would then not have a prediction. Instead I have decided to predict all future games, and update as required to ensure that before a team plays, my predictions will take into account all previous games.

Observe below that means for example that I will provide updated predictions before the Georgia vs. Uruguay game to take into account the game played by Uruguay against Fiji.

Team Ratings 2

The basic method is described on my Department home page.
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
New Zealand 27.68 27.60 0.10
England 19.04 19.78 -0.70
South Africa 18.42 18.51 -0.10
Ireland 13.68 12.12 1.60
Wales 12.62 12.72 -0.10
Australia 9.06 8.70 0.40
France 7.02 7.11 -0.10
Argentina 4.23 4.15 0.10
Scotland 3.88 5.44 -1.60
Fiji -5.64 -5.27 -0.40
Japan -9.08 -7.67 -1.40
Italy -9.31 -8.57 -0.70
Samoa -11.89 -11.89 -0.00
USA -16.38 -16.38 -0.00
Georgia -17.32 -17.43 0.10
Tonga -19.72 -20.46 0.70
Canada -32.45 -32.45 0.00
Russia -35.38 -36.78 1.40
Uruguay -35.67 -35.67 -0.00
Namibia -41.06 -41.80 0.70

 

Performance So Far

So far there have been 8 matches played, 8 of which were correctly predicted, a success rate of 100%.
Here are the predictions for the previous games.

Game Date Score Prediction Correct
1 Japan vs. Russia Sep 20 30 – 10 35.60 TRUE
2 Australia vs. Fiji Sep 21 39 – 21 14.00 TRUE
3 France vs. Argentina Sep 21 23 – 21 3.00 TRUE
4 New Zealand vs. South Africa Sep 21 23 – 13 9.10 TRUE
5 Italy vs. Namibia Sep 22 47 – 22 33.20 TRUE
6 Ireland vs. Scotland Sep 22 27 – 3 6.70 TRUE
7 England vs. Tonga Sep 22 35 – 3 40.20 TRUE
8 Wales vs. Georgia Sep 23 43 – 14 30.10 TRUE

 

Predictions 2

Here are the updated predictions. 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 Russia vs. Samoa Sep 24 Samoa -23.50
2 Fiji vs. Uruguay Sep 25 Fiji 30.00
3 Italy vs. Canada Sep 26 Italy 23.10
4 England vs. USA Sep 26 England 35.40
5 Argentina vs. Tonga Sep 28 Argentina 24.00
6 Japan vs. Ireland Sep 28 Ireland -16.30
7 South Africa vs. Namibia Sep 28 South Africa 59.50
8 Georgia vs. Uruguay Sep 29 Georgia 18.30
9 Australia vs. Wales Sep 29 Wales -3.60
10 Scotland vs. Samoa Sep 30 Scotland 15.80
11 France vs. USA Oct 02 France 23.40
12 New Zealand vs. Canada Oct 02 New Zealand 60.10
13 Georgia vs. Fiji Oct 03 Fiji -11.70
14 Ireland vs. Russia Oct 03 Ireland 49.10
15 South Africa vs. Italy Oct 04 South Africa 27.70
16 Australia vs. Uruguay Oct 05 Australia 44.70
17 England vs. Argentina Oct 05 England 14.80
18 Japan vs. Samoa Oct 05 Japan 9.30
19 New Zealand vs. Namibia Oct 06 New Zealand 68.70
20 France vs. Tonga Oct 06 France 26.70
21 South Africa vs. Canada Oct 08 South Africa 50.90
22 Argentina vs. USA Oct 09 Argentina 20.60
23 Scotland vs. Russia Oct 09 Scotland 39.30
24 Wales vs. Fiji Oct 09 Wales 18.30
25 Australia vs. Georgia Oct 11 Australia 26.40
26 New Zealand vs. Italy Oct 12 New Zealand 37.00
27 England vs. France Oct 12 England 12.00
28 Ireland vs. Samoa Oct 12 Ireland 25.60
29 Namibia vs. Canada Oct 13 Canada -8.60
30 USA vs. Tonga Oct 13 USA 3.30
31 Wales vs. Uruguay Oct 13 Wales 48.30
32 Japan vs. Scotland Oct 13 Scotland -6.50

 

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September 18, 2019

How single transferable vote works

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NZ is having local elections.  Some of the elections work by single transferable vote.  The working of STV are not precisely statistics, but they’re nerdy enough in a vaguely mathematical way to be on topic.  And I’ve run the counting of STV elections (for the Monash Association of Students), so I have a pretty good grasp of how it works.

Rather than explain it to you, though, I’m going to outsource to Graeme Edgeler’s nice and accurate explanation.

 

 

Briefly

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September 17, 2019

NRL Predictions for Finals Week 2

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Team Ratings for Finals Week 2

The basic method is described on my Department home page.
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 11.99 8.72 3.30
Storm 11.65 6.03 5.60
Raiders 6.97 1.81 5.20
Eels 4.32 -6.17 10.50
Rabbitohs 2.49 3.89 -1.40
Sharks 1.81 3.90 -2.10
Sea Eagles 1.32 -5.61 6.90
Panthers -0.13 0.93 -1.10
Wests Tigers -0.18 -5.57 5.40
Bulldogs -2.52 -0.61 -1.90
Cowboys -3.95 0.15 -4.10
Warriors -5.17 -0.27 -4.90
Broncos -5.53 2.63 -8.20
Knights -5.92 -8.51 2.60
Dragons -6.14 0.06 -6.20
Titans -12.99 -3.36 -9.60

 

Performance So Far

So far there have been 196 matches played, 126 of which were correctly predicted, a success rate of 64.3%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Roosters vs. Rabbitohs Sep 13 30 – 6 10.60 TRUE
2 Storm vs. Raiders Sep 14 10 – 12 9.30 FALSE
3 Sea Eagles vs. Sharks Sep 14 28 – 16 1.00 TRUE
4 Eels vs. Broncos Sep 15 58 – 0 5.50 TRUE

 

Predictions for Finals Week 2

Here are the predictions for Finals Week 2. 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 Rabbitohs vs. Sea Eagles Sep 20 Rabbitohs 4.20
2 Storm vs. Eels Sep 21 Storm 10.30

 

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Mitre 10 Cup Predictions for Round 7

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Team Ratings for Round 7

The basic method is described on my Department home page.
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
Tasman 16.89 9.00 7.90
Canterbury 16.22 12.92 3.30
Auckland 11.07 11.57 -0.50
Wellington 8.17 10.92 -2.70
Bay of Plenty 4.68 -4.82 9.50
Waikato 4.53 8.24 -3.70
North Harbour 4.09 5.30 -1.20
Hawke’s Bay -1.66 -5.69 4.00
Counties Manukau -3.06 -1.99 -1.10
Taranaki -3.40 -5.22 1.80
Otago -5.97 -1.49 -4.50
Northland -12.66 -6.23 -6.40
Manawatu -15.38 -11.67 -3.70
Southland -24.75 -22.08 -2.70

 

Performance So Far

So far there have been 42 matches played, 29 of which were correctly predicted, a success rate of 69%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Waikato vs. Hawke’s Bay Sep 12 24 – 27 13.10 FALSE
2 Northland vs. Canterbury Sep 13 12 – 42 -23.80 TRUE
3 Taranaki vs. Bay of Plenty Sep 14 17 – 31 -1.90 TRUE
4 Southland vs. Manawatu Sep 14 26 – 31 -5.50 TRUE
5 Counties Manukau vs. Auckland Sep 14 13 – 28 -9.10 TRUE
6 Wellington vs. Otago Sep 15 54 – 24 15.50 TRUE
7 Tasman vs. North Harbour Sep 15 21 – 17 19.60 TRUE

 

Predictions for Round 7

Here are the predictions for Round 7. 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 Canterbury vs. Manawatu Sep 19 Canterbury 35.60
2 Hawke’s Bay vs. Taranaki Sep 20 Hawke’s Bay 5.70
3 Waikato vs. Tasman Sep 21 Tasman -8.40
4 Southland vs. Counties Manukau Sep 21 Counties Manukau -17.70
5 North Harbour vs. Otago Sep 21 North Harbour 14.10
6 Auckland vs. Wellington Sep 22 Auckland 6.90
7 Northland vs. Bay of Plenty Sep 22 Bay of Plenty -13.30

 

September 14, 2019

Hadley Wickham talks to Kim Hill

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Hadley is Chief Scientist of RStudio, an alumnus and adjunct Professor here in the Department of Statistics, and the recent winner of the Presidents’ Award from the Committee of Presidents of Statistical Societies, one of the top honours in statistics.

That’s two celebrity statisticians interviewed by Kim Hill in consecutive weeks, which must be some sort of record.

Listen here

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