Posts filed under General (571)

October 22, 2014

Currie Cup Predictions for the Currie Cup Final

Team Ratings for the Currie Cup Final

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
Lions 7.39 0.07 7.30
Western Province 5.87 3.43 2.40
Sharks 3.00 5.09 -2.10
Blue Bulls 1.17 -0.74 1.90
Cheetahs -3.53 0.33 -3.90
Pumas -8.20 -10.00 1.80
Griquas -10.10 -7.49 -2.60
Kings -14.91 -10.00 -4.90

 

Performance So Far

So far there have been 42 matches played, 31 of which were correctly predicted, a success rate of 73.8%.

Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Lions vs. Sharks Oct 18 50 – 20 6.70 TRUE
2 Western Province vs. Blue Bulls Oct 18 31 – 23 10.00 TRUE

 

Predictions for the Currie Cup Final

Here are the predictions for the Currie Cup Final. 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 Western Province vs. Lions Oct 25 Western Province 3.50

 

ITM Cup Predictions for the ITM Cup Finals

Team Ratings for the ITM Cup Finals

Here are the team ratings prior to the ITM Cup Finals, along with the ratings at the start of the season. I have created a brief description of the method I use for predicting rugby games. Go to my Department home page to see this.

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 12.36 5.78 6.60
Canterbury 12.25 18.09 -5.80
Counties Manukau 6.58 2.40 4.20
Taranaki 6.27 -3.89 10.20
Auckland 4.84 4.92 -0.10
Hawke’s Bay 0.47 2.75 -2.30
Wellington -2.74 10.16 -12.90
Manawatu -2.90 -10.32 7.40
Otago -3.98 -1.45 -2.50
Northland -4.05 -8.22 4.20
Waikato -5.74 -1.20 -4.50
Southland -6.07 -5.85 -0.20
Bay of Plenty -9.23 -5.47 -3.80
North Harbour -10.13 -9.77 -0.40

 

Performance So Far

So far there have been 74 matches played, 48 of which were correctly predicted, a success rate of 64.9%.

Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Hawke’s Bay vs. Northland Oct 17 26 – 21 9.30 TRUE
2 Manawatu vs. Southland Oct 18 23 – 18 7.70 TRUE
3 Taranaki vs. Auckland Oct 18 49 – 30 3.00 TRUE
4 Tasman vs. Canterbury Oct 18 26 – 6 1.30 TRUE

 

Predictions for the ITM Cup Finals

Here are the predictions for the ITM Cup 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 Manawatu vs. Hawke’s Bay Oct 24 Manawatu 0.60
2 Taranaki vs. Tasman Oct 25 Tasman -2.10

 

October 19, 2014

Broadening your data display palate — multivariate beer?

Nathan Yau at Flowing Data has a project page on multivariate beer. That is, he wants to use beer recipes to encode information about US counties taken from the American Community Survey:

The great thing about beer is that it has plenty of dimensions to work with: body, bitterness, head retention, hop profile, color, aroma, alcohol by volume, and plenty more. The amount of various ingredients affects how beer looks, tastes, and smells.

Still a work in progress, here’s how a beer recipe is formed.

  • Greater head retention should increase with higher education, so a grain called Carapils is added.More hop aroma represents higher employment. This comes from more hops at the end of a boil and dry hopping.
  • Rye adds spice and complexity to the beer as health care coverage increases.
  • A darker-colored and more full-bodied beer comes from higher median household income and Crystal Malt 40.
  • More hop bitterness and flavor means more people per square mile, and the type of hops — Cascade, Centennial, Citra, Warrior, and Magnum — represents the races of the population.

That sounds fun, but I’m not convinced by its possibilities for data communication.

People often want to use other senses than vision for data communication, because they would provide more dimensions.  There are a couple of problems with this. First, the bandwidth and resolution of the other senses aren’t as good — for example, even a professional tea-taster can’t manage much over a thousand data points per day. Second, there’s encoding: the idea is to take advantage of the richness of experience from using all the senses, but it’s hard enough to work out how to encode numbers visually, and it will be much harder to come up with encodings for the other senses that convey accurate quantitative information.

October 18, 2014

Briefly

1. There’s a conference coming up in Canada on “Fairness, Accountability, and Transparency in Machine Learning”, a topic I wrote a little about for the Listener

Questions to the machine learning community include:

  • How can we achieve high classification accuracy while eliminating discriminatory biases? What are meaningful formal fairness properties?
  • How can we design expressive yet easily interpretable classifiers?
  • Can we ensure that a classifier remains accurate even if the statistical signal it relies on is exposed to public scrutiny?
  • Are there practical methods to test existing classifiers for compliance with a policy?

(via mathbabe.org)

2. From Nate Silver at fivethirtyeight.com

Democrats may not be wrong. The polls could very well be biased against their candidates. The problem is that the polls are just about as likely to be biased against Republicans, in which case the GOP could win more seats than expected.

This sort of slowly varying bias is probably one of the reasons the NZ election polls weren’t very good: not only did they have more variability than you’d expect given the sample sizes, but averaging didn’t cancel out much of the error.

3. Yesterday was Spreadsheet Day. Flee in terror! (via @kara_woo)

4. An informative  visualisation of what the world eats, over time. (via Harkanwal Singh)

 

October 16, 2014

Do you feel lucky?

I’m glad to say it’s been quite a while since we’ve had this sort of rubbish from the NZ papers, but it’s still  going across the Tasman (the  Sydney Morning Herald)

If you’re considering buying a lottery ticket, you’d better make sure it’s from either Gladesville or Cabramatta, which are now officially Sydney’s luckiest suburbs when it comes to winning big. 

NSW Lotteries has released statistics that show the luckiest suburbs across all lotto games in NSW and the ACT, as well as other tips for amateurs hoping to ring their bosses tomorrow morning to say they wouldn’t be coming in to work. 

Of course, the ‘luckiest’ suburbs are nothing of the sort: just the ones where the most money is lost on the lotteries. Cabramatta has improved a lot in recent years, but it’s still not the sort of place you’d expect to see called ‘lucky’.

October 15, 2014

Currie Cup Predictions for the Semi-Finals

Team Ratings for the SemiFinals

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
Lions 6.03 0.07 6.00
Western Province 6.02 3.43 2.60
Sharks 4.36 5.09 -0.70
Blue Bulls 1.02 -0.74 1.80
Cheetahs -3.53 0.33 -3.90
Pumas -8.20 -10.00 1.80
Griquas -10.10 -7.49 -2.60
Kings -14.91 -10.00 -4.90

 

Performance So Far

So far there have been 40 matches played, 29 of which were correctly predicted, a success rate of 72.5%.

Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Kings vs. Pumas Oct 10 26 – 25 -2.20 FALSE
2 Lions vs. Cheetahs Oct 11 47 – 7 11.30 TRUE
3 Western Province vs. Sharks Oct 11 20 – 28 8.70 FALSE
4 Blue Bulls vs. Griquas Oct 11 46 – 12 13.70 TRUE

 

Predictions for the SemiFinals

Here are the predictions for the SemiFinals. 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 Lions vs. Sharks Oct 18 Lions 6.70
2 Western Province vs. Blue Bulls Oct 18 Western Province 10.00

 

ITM Cup Predictions for the ITM Cup Finals

Team Ratings for the ITM Cup Finals

Here are the team ratings prior to the ITM Cup Finals, along with the ratings at the start of the season. I have created a brief description of the method I use for predicting rugby games. Go to my Department home page to see this.

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
Canterbury 13.65 18.09 -4.40
Tasman 10.97 5.78 5.20
Counties Manukau 6.58 2.40 4.20
Auckland 6.05 4.92 1.10
Taranaki 5.06 -3.89 9.00
Hawke’s Bay 0.84 2.75 -1.90
Manawatu -2.66 -10.32 7.70
Wellington -2.74 10.16 -12.90
Otago -3.98 -1.45 -2.50
Northland -4.42 -8.22 3.80
Waikato -5.74 -1.20 -4.50
Southland -6.31 -5.85 -0.50
Bay of Plenty -9.23 -5.47 -3.80
North Harbour -10.13 -9.77 -0.40

 

Performance So Far

So far there have been 70 matches played, 44 of which were correctly predicted, a success rate of 62.9%.

Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Counties Manukau vs. Auckland Oct 08 41 – 18 1.40 TRUE
2 Waikato vs. Bay of Plenty Oct 09 29 – 12 5.70 TRUE
3 Otago vs. Manawatu Oct 10 25 – 38 5.40 FALSE
4 Wellington vs. North Harbour Oct 11 58 – 34 9.10 TRUE
5 Hawke’s Bay vs. Southland Oct 11 20 – 20 13.20 FALSE
6 Auckland vs. Northland Oct 11 38 – 10 13.60 TRUE
7 Taranaki vs. Canterbury Oct 12 23 – 26 -5.00 TRUE
8 Tasman vs. Counties Manukau Oct 12 16 – 21 12.40 FALSE

 

Predictions for the ITM Cup Finals

Here are the predictions for the ITM Cup 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 Hawke’s Bay vs. Northland Oct 17 Hawke’s Bay 9.30
2 Manawatu vs. Southland Oct 18 Manawatu 7.70
3 Taranaki vs. Auckland Oct 18 Taranaki 3.00
4 Tasman vs. Canterbury Oct 18 Tasman 1.30

 

October 14, 2014

Does it make any more sense this time?

From the Herald today

“The average annual weekly wage increase of $28.06 was not enough to offset a $30,000 increase in the national median house price and an increase in the average mortgage interest rate from 5.52% to 5.86%,” the survey found.

We did this one last time, in June. Today’s story is better in that it links to the Massey report. It could still do with a bit of interpretation.

Quick, without a calculator, roughly what would be a large enough weekly wage increase to offset a $30,000 increase in the national median house price?  Would we need to up the $28.06 by ten percent, or  ten dollars, or a factor of ten?

[Update: I should also note that the word "weekly" wasn't in the description of wage increases last time, so this is a definite improvement]

Ada Lovelace Day

October 14 is Ada Lovelace Day, an international celebration of the achievements of women in science, technology, engineering and maths.

New Zealand has (only) three female Professors of Statistics, the top position in our UK-style academic ranking. They work in very different areas of statistics, but with related applications to ecological and environmental monitoring, an area of particular interest in New Zealand.

Going north to south:

  • Marti Anderson is at Massey University in Albany (and was previously at the University of Auckland). Her research is in multivariate analysis — techniques for analysing ecological data on multiple species together, rather than one at a time — mostly applied to marine species
  • Shirley Pledger retired this year from Victoria University. Her research is on capture-recapture methods for counting animals. It’s often impossible to get a complete census of a species even in a limited area, but you can mark the individuals you catch, release them, and observe how often you catch them again. The simplest approaches to estimation are easy but unrealistic; she has worked on more sophisticated and sensible models.
  • Jennifer Brown is head of the Maths & Stats department at the University of Canterbury. Her main statistical research is on sampling techniques for monitoring sparse or patchy populations: either rare animals and plants, or invasive weeds. Sampling systematically or purely at random are both very wasteful; ‘adaptive’ sampling designs allow you to take advantage of finding a clump of your target species without biasing the overall results.

 

October 10, 2014

Briefly

  • Something strange happened to this month’s unemployment data in Australia: Guardian, ABC News, interview with Rob Hyndman (who knows from time series)
  • “Ferguson’s 3,287 new registrants (in two months) is more than recorded by any township in St. Louis County in any midterm election since 2002.” Or not. A number that seems really extreme may just be wrong.
  • When there’s a lot of variation, it can be a mistake to make statements about “typical” attitudes: Andrew Gelman