Posts from December 2019 (14)

Multiple people have pointed me to this picture, authorised by Simon Bridges.

It’s designed to look like a barchart, but if it were a barchart the dimensions of the colored bits would have a closer quantitative relation to the numbers being displayed. I’m going to assume the numbers are correct, because that’s the sort of thing people are more careful about. The bars aren’t.

To start with, the red bar is wider than the blue bar, which is a well-known graphical exaggeration technique. But that’s not the real problem. The real problem is the heights.

On my laptop screen, I measured the red bar as 61% higher than the blue bar. But $2.23/L is only 16% higher than $1.91/L: that’s nearly a four-fold exaggeration of the difference

The dark red ‘Tax’ section of the red bar is 92% higher than the dark blue ‘Tax’ section of the blue bar, but $1.12 is only 29% higher than $0.87: more than a three-fold exaggeration.

If the heights were proportional to the numbers, as in a real barchart, it would look like this:

But wait, there’s more!  The blue bar is averaged over nine years of National government; the red bar is from last week.  That means the difference between the blue and red bars is partly inflation.  Over the time since September 2008, the RBNZ calculator says there has been 18% inflation.  We could say, as a rough approximation, that the data spread over nine years should get half the inflation applied.  Doing this would wipe out about half the difference between the blue and red bars, to give a comparison like this one:

There has been an increase in petrol prices due to tax increases under Labour. It’s not anywhere near as big as National’s graphic implies.

Q: Did you see that a harrowing study of 46,000 women shows hair dyes are heavily associated with cancer?

A: Harrowing?

Q: According to FastCompany.

A: That’s just the headline, though.

Q: “You know how you don’t see very old people with dyed hair? There may be a reason for that: Hair dye is heavily associated with cancer.”

A: That would be a heavy association.

Q: So is it true? There’s a link, even.

A: “We observed a 9% higher breast cancer risk for permanent dye use in all women but little to no associated risk for semipermanent or temporary dye use.”

Q: That’s… not as harrowing as I expected. Would that kill off a big fraction of hair-dye users?

A: Well, not very many men. For women the lifetime risk, which is the cumulative risk by the time you’re ‘very old’, is about 1 in 8. Increasing that by 9% would be about one extra breast cancer case per hundred hair-dye users.

Q:  So that’s not why very old people don’t use hair dye

A: There are probably other factors in play, yes.

Q: It’s just breast cancer, though. What about the effect on other cancers?

A: They didn’t look.  They mostly expected a risk on breast cancer, because of theories about ‘estrogen disruption’.

Q:  The story says the effects are bigger in Black women.

A: It looks like they probably are, though there’s a lot of uncertainty because Black women were only 10% of the study.

Q: Nothing about hair dye in men?

A: It was a study of sisters of people with breast cancer, so no men.

Q: Also too, no generalisability?

A: It’s not quite that bad, but, yes, it’s not clear how well this generalises. It could be that these women are more susceptible to hair dyes. Or not.

Q: What did previous research find?

A: It’s mixed. A big study in Black women in the 1990s didn’t find an association, but another current study did.

Q: So do we believe it?

A: We aren’t Black women who use hair dye. On several counts.

Q:

A: It certainly could be true, but the evidence isn’t overwhelming.

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.

Performance So Far

So far there have been 49 matches played, 38 of which were correctly predicted, a success rate of 77.6%.
Here are the predictions for last week’s games.

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.

Team Ratings for Round 6

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 30 matches played, 23 of which were correctly predicted, a success rate of 76.7%.
Here are the predictions for last week’s games.

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.