Stats Chat

Q: Are you going to have a glass of wine tonight?

A: You mean as a celebration?.

Q: No, because a glass of red wine has the same benefits as a gym session. The Herald story?

A: Yeah, nah.

Q: What part of “Red wine equal to a gym workout – study” don’t you understand?

A: How they got that from the research.

Q: Was this just correlations again?

A: No, it was a real experimental study.

Q: So I’m guessing you’re going to say “in mice”?

A: Effectively. It was in rats.

Q: They gave some rats red wine and made others do gym workouts?

A: No, there wasn’t any red wine.

Q: But the story… ah, I see. “A compound found in red wine”. They gave the rats this compound directly?

A: That’s right

Q: And the gym workouts?

A: Basically, yes. The rats did treadmill runs, though they don’t report that they had headphones on at the time.

Q: So the resveratrol group ended up fitter than the exercise group?

A: No, both groups got the workouts. The resveratrol plus exercise group ended up fitter than the group just getting exercise.

Q: So, really, it’s about a glass of red wine plus a gym workout, not instead of a gym workout? If it was people, not rats?

A: Well, not “a glass”.

Q: How many glasses?

A: The rats got 146mg resveratrol per kg of weight per day. One standard conversion rate is to divide by 7 to get mg/kg in humans: about 20. So for a 60kg person, that’s about 1200mg/day of resveratrol.

Q: How much is in a glass of wine?

A: It depends on the size, but at 5 glasses per bottle, maybe 0.3 mg

Q: So we might need bigger glasses, then.

A: At least you’ll get plenty of exercise lifting them.

Team Ratings for the Semi-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 Rugby World Cup.

Performance So Far

So far there have been 44 matches played, 37 of which were correctly predicted, a success rate of 84.1%.
Here are the predictions for last week’s games.

Predictions for the Semi-finals

Here are the predictions for the Semi-finals. The prediction is my estimated expected points difference with a positive margin being a win to the first-named team, and a negative margin a win to the second-named team.

Team Ratings for the ITM Cup 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.

Performance So Far

So far there have been 74 matches played, 53 of which were correctly predicted, a success rate of 71.6%.
Here are the predictions for last week’s games.

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.

Team Ratings for the Currie Cup Final

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.

Performance So Far

So far there have been 42 matches played, 30 of which were correctly predicted, a success rate of 71.4%.
Here are the predictions for last week’s games.

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.

[this post by Julie Middleton]

Today is World Statistics Day, and statisticians all over the world will be showcasing the value of their work under the theme ‘Better data, better lives’.
To mark the day, Statistics New Zealand is putting out three useful resources:[

1: An animated infographic that expresses the value of statistics to the economy and people as they go about their day-to-day lives;

2: A video that summarises in two minutes changes in New Zealand’s population over the last 150 years;

3: A video that summarises the highs and lows of 30 years of labour market statistics.

World Statistics Day was proclaimed by the United Nations General Assembly in 2010 to recognise the importance of statistics in shaping our societies. National and regional statistical days already existed in more than 100 countries, but the General Assembly’s adoption of this international day as 20 October brought extra momentum. That first World Statistics Day in October 2010 was marked in more than 130 countries and areas.

According to UNStats, this year marks an important cornerstone for official statistics, with the conclusion of the Millennium Development Goals (see how countries have fared here), the post-2015 development agenda, the data revolution (see what the Data Revolution Group set up by UN Secretary-General Ban Ki-Moon has to say here), the preparations for the 2020 World Population and Housing Census Programme and the likes.
One cute initiative of UNStats is to translate the English logo for World Statistics Day into many of the languages of the world. We couldn’t miss the opportunity to have UNStats do one in the first language of this country, te reo Māori. Te tino kē hoki o te moko nā! (Nice logo!)

You can download logos in English, Māori and dozens of other languages from the UNStats site here.

One important initiative of the UN for this year’s commemoration is the launch, at its New York headquarters, of the report The World’s Women 2015: Trends and Statistics. The report is produced every five years under the Beijing Platform for Action, which was adopted at the Fourth World Conference on Women in 1995.

The eight chapters of the report cover several critical areas of policy concerns identified in that landmark 1995 conference: population and families; health; education; work; power and decision-making; violence against women; environment; and poverty. It takes a life-cycle approach in revealing the experiences of women and men during different periods of life.

• Good piece in the Herald (from Barry Ritholtz at Bloomberg View) on the need for context, and especially for denominators, in handling big headline numbers.  Not news to StatsChat readers.

• The Guardian says “‘We have to start talking about it’: New Zealand suicide rates hit record high.” The first bit is true. The second, as I explained a couple of weeks ago, isn’t. The rate isn’t at a record high (the count is), and more generally the tragedy (or scandal) is that the rate has been basically this high for a long time. This graph is on the front page of the report from the Chief Coroner
  

• No, I don’t know why moles on your  right arm are particularly relevant to melanoma.  I don’t know because the British Journal of Dermatology told the media to print the story before they released the scientific paper. Yes, there’s a lot of this around.

• I am pretty sure, though, that customising a UK story about melanoma with “In New Zealand, new skin cancers total about 67,000 per year” isn’t helpful. That’s all skin cancers. For melanoma the figure is about 2500 (from the Ministry of Health) or about 4000 (from Melanoma NZ). I think the difference between the two figures may be that the Ministry of Health don’t count melanoma in situ. Either way, not 67,000.

• Experimental evidence that decorating your barcharts with round bits or pointy bits really makes them less readable. (via @albertocairo)

• Nicholas Felton has been collecting data about himself and making art in the form of Personal Annual Reports for ten years. His latest and last is out now.

• New factsheets from the (UK) Patient Information Forum, on communicating risk (via David Spiegelhalter)

• People are more afraid of shark attacks than car accidents despite the fact that car accidents are much more likely. SMBC has a solution to this problem. It involves marine biology. (via @scicomguy)

UMR have done a survey of preferences on the new flag candidates that can be used to predict the preferential-voting result.  According to their data, while Red Peak has improved a long way from basically no support in August, it has only improved enough to be a clear third to the two Lockwood ferns, which are basically tied for the lead both on first preferences and on full STV count.  On the other hand, none of the new candidates is currently anywhere near beating the current version.

The error in a poll like this is probably larger than in an election poll, because there’s no relevant past data to work with. Also, for the second round of the referendum, it’s possible that cutting the proposals down to a single alternative will affect opinion. And, who knows, maybe Red Peak will keep gaining popularity.

There are useful pieces by David Fisher in the Herald, and Tom Pullar-Strecker at Stuff, about the new NZ Data Futures Partnership and its chair, Dame Diane Robertson.  The idea is that the government has access to a lot of data, which could be used in all sorts of ways, but that New Zealand society needs to make decisions about which uses are ok. At least, that’s the idea in David Fisher’s story. In the Stuff piece it sounds more as though the idea is to educate people so they agree with the desired uses. [update: in the print version of the Herald there’s also something by Harkanwal Singh on the social consent issue]

Detailed individual data can be used for predicting things, and while there’s obviously a problem if the predictions are inaccurate, there can be even more of a problem if they are accurate. The Herald story mentions the use of predictions of re-offending to give people longer prison terms, so-called ‘evidence-based sentencing‘.

It isn’t just a question of whether data will be used to do Bad Things, though. There’s a broader problem of maintaining trust in government data. If you think your information is going to be used to do complex, mysterious, and potentially creepy things, you’re going to be less likely to talk to the nice StatsNZ interviewer.  Reliable government data collection is important for the private sector as well as the public sector, and it’s much more difficult and expensive if the public don’t trust the data collectors.

In the US, according to a recent analysis, confidence in federal statistical agencies is fairly low — they’re rated more highly than the politicians, but below the military and universities, and level with newspapers.

In this survey, it mattered how much people knew about the statistical agencies, but in a complicated way. For people who didn’t know much about what the agencies did, confidence in them was moderately well correlated with confidence in the military, newspapers, Congress, and universities. For people who knew more about the agencies, these correlations were weaker.  These people might like or dislike the Census Bureau or the CDC, but didn’t see the agencies as part of a vague and powerful Them.

There are plenty of cynical explanations you can give for these results, but there’s also an obvious positive explanation: it’s good for people to understand what government does with their data and why.

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 October 23 2015.
• Statistics can be bad, exemplary or fascinating.
• The statistic must be in the NZ media during the period of October 17 – 23 2015 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.

(more…)

I was surprised to see a headline in the Business section of the Herald saying “2015 luckiest year for Lotto players” about lotto jackpots (story here)

After all, the way the lottery jackpots work, the amount paid out is a fixed fraction of the amount taken in. If there are more people winning large amounts then either the large amounts aren’t as large as in other years, or it’s because more people are collectively losing large amounts. Lotto players, considered individually, can be lucky or not; lotto players conside collectively, can’t be.

If you look carefully, though, you can see this isn’t a news story. It’s a “Sponsored Story”.

This still seems different from the “Brand Insight” that “connects readers directly to the leadership thinking of many prominent companies and organisations“, or the science and technology column by Michelle ‘Nanogirl’ Dickinson that was initially sponsored by Callaghan Innovation.