Stats Chat

Team Ratings for Week 1

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.

Predictions for Week 1

Here are the predictions for Week 1. 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 Round 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.

Performance So Far

So far there have been 4 matches played, 3 of which were correctly predicted, a success rate of 75%.
Here are the predictions for last week’s games.

Predictions for Round 2

Here are the predictions for Round 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.

Team Ratings for Week 22

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 170 matches played, 114 of which were correctly predicted, a success rate of 67.1%.
Here are the predictions for last week’s games.

Predictions for Week 22

Here are the predictions for Week 22. 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 Round 1

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.

Predictions for Round 1

Here are the predictions for Round 1. 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.

From XKCD, the most commonly reported plant and animal on iNaturalist for each US state (click to embiggen)

This is mostly about selection biases of various types: how recognisable the plant or animal is and how interesting.  Saguaro, in Arizona, are not exactly rare, but they aren’t the most commonly seen plant. They are famously associated with the southwest desert and immediately recognisable, so they get reported often.  In other states, the most common plant is genuinely common: yarrow in Montana, California Poppy in California, Amur honeysuckle (sadly) in some Kentucky and Indiana.

So what is it in New Zealand? Looking at the “research-grade” reports, because it’s easier, the most common animal seems to be the kererū, with the pīwakawaka second. Easy to recognise, popular, interesting. For plants, it’s the māhoe, which I wasn’t expecting.

Team Ratings for Round 21

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 148 matches played, 93 of which were correctly predicted, a success rate of 62.8%.
Here are the predictions for last week’s games.

Predictions for Round 21

Here are the predictions for Round 21. 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 Week 21

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 161 matches played, 107 of which were correctly predicted, a success rate of 66.5%.
Here are the predictions for last week’s games.

Predictions for Week 21

Here are the predictions for Week 21. 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.

• In “where are they now” followup: a 2016 StatsChat post examining a claim that dementia cures were just five years away. They weren’t.
• Data Strips: A nice lookup at ways to show the distribution of a single numeric variable “in-line”
• As foreshadowed by XKCD, mobile phone acceleration sensors are now genuinely warning of earthquakes-in-progress (media, research paper)
• Stuff reports a reported sighting of the South Island kōkako. From the South Island Kōkako Trust (via Mike Dickison), a map just of probable encounters with South Island kōkako (ie, leaving out their large collection of “possible” encounters). They’re everywhere!
  
  That’s the problem. If they really existed in any significant fraction of the places they’ve been reported, you would expect them to be seen a lot more often including by people with cameras at the ready.  It’s not really feasible for a bird to be on the edge of vanishing, all over the South Island simultaneously, for decades, which is why I think it’s an ex-parrot.

As you probably have heard, tap water in Gore has been running just above the regulatory maximum of 11.3mg/L of nitrate. Nitrate in high enough doses converts hemoglobin to an inactive form, and babies are more susceptible. There are other risks, but they are more speculative according to the CDC. The risk should be pretty low when the concentration is just above the regulatory limit — that’s the point of regulatory limits — and it’s mostly for babies and pregnant women. Still: not ideal, and  you don’t want to let water standards start to slip.

That first link, though, is from 1News.  A couple of months ago they ran a story headed Seven things to eat or avoid to lower your blood pressure. Number 2 on the list is beetroot, based on its high nitrate content. Yes, the same nitrate that’s in the water in Gore. Beetroot juice contains quite a lot more nitrate. A research paper on sports supplements suggests the effective dose would be about 5 mmol per serving, which translates to a bit more than 300 mg, or more than 25 litres of Gore tapwater.

Obviously there’s difference between sports nerds deliberately drinking beetroot for the nitrates and nitrates turning up as an unwanted contaminant for young and old.  The risks are different, and consent matters. Still, it’s a recurrent irritation that the “nitrates good in massive doses” and “nitrates bad even in small doses” stories don’t get cross-referenced a bit more in the media, and we don’t have a more quantitative approach to the risk.  If we’re supposed to believe it’s actually risky to brush your teeth with water that’s 1% above the regulatory limit, the limit is in the wrong place.

• Stuff has Eye-watering new food price stats just revealed: Price of butter has nearly doubled in a year. If you read a bit further it turns out “Butter surged to $8.60 per 500g, a 46.5% annual increase”.  A 50% increase isn’t doubling.  If it had doubled it would be $11.80 per 500g, not $8.60. Those are importantly different numbers.
• The Royal Statistical Society has given out its annual “Statistical Excellence in Journalism” awards: Some of the winners: How many toddlers and babies are living in temporary accommodation in the UK?  and The rise in reported maternal mortality rates in the US is largely due to a change in measurement and an interactive tool linking information about members of the House of Lords, and  about how a crime victimisation figure excludes stalking, sexual assault, and some other crimes
• To add to all the rugby here, Achim Zeileis and colleagues have probabilistic forecasts for the UEFA Women’s Euro 2025 competition