June 24, 2013
Stat of the Week Competition: June 22 – 28 2013
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 June 28 2013.
- Statistics can be bad, exemplary or fascinating.
- The statistic must be in the NZ media during the period of June 22 – 28 2013 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.
The fine print:
- Judging will be conducted by the blog moderator in liaison with staff at the Department of Statistics, The University of Auckland.
- The judges’ decision will be final.
- The judges can decide not to award a prize if they do not believe a suitable statistic has been posted in the preceeding week.
- Only the first nomination of any individual example of a statistic used in the NZ media will qualify for the competition.
- Individual posts on Stats Chat are just the opinions of their authors, who can criticise anyone who they feel deserves it, but the Stat of the Week award involves the Department of Statistics more officially. For that reason, we will not award Stat of the Week for a statistic coming from anyone at the University of Auckland outside the Statistics department. You can still nominate and discuss them, but the nomination won’t be eligible for the prize.
- Employees (other than student employees) of the Statistics department at the University of Auckland are not eligible to win.
- The person posting the winning entry will receive a $20 iTunes voucher.
- The blog moderator will contact the winner via their notified email address and advise the details of the $20 iTunes voucher to that same email address.
- The competition will commence Monday 8 August 2011 and continue until cancellation is notified on the blog.
Rachel Cunliffe is the co-director of CensusAtSchool and currently consults for the Department of Statistics. Her interests include statistical literacy, social media and blogging. See all posts by Rachel Cunliffe »
Statistic: Study: Breast best for success
Babies who were breastfed:
• 24 per cent more likely to have a “better” category of job than their father did.
• 20 per cent less likely to have a “worse” category of job.
• Based on a study of 34,000 people born in 1958 or 1970.
Source: NZ Herald
Date: 26/06/13
I think this is something about correlation and causation. Though this results is doubted statistically, this is good to encourage mothers to breastfeed their babies.
11 years ago
Statistic: Overall, Labour has fallen from 36.5 per cent in the March poll to 30.9 per cent in the June poll published today. NZ First has risen from 2.5 per cent in March to 5.1 per cent now, based on the poll of 750 respondents.
…
Party vote figures in the poll are: … Act 0.2 (up 0.1).
Source: NZ Herald
Date: Wednesday Jun 26, 2013
There are several things confusing about this article, one thing being the way percentage values are quoted to 1dp, even though the poll has “a margin of error of plus or minus 3.6 per cent.” This gives an impression of accuracy that the poll doesn’t appear to deserve.
Also, party vote results “are of decided voters only,” and 11.9 per cent of respondents were undecided. I make that out to be 661 decided voters, not the 750 the initial comments imply. While this point is clarified at the bottom of the article, to say that Act polls 0.2% (up 0.1) makes no sense. 0.2% of 661 people is 1.32 people. It seems clear that the % of a single voter (0.15%) has been rounded up. So Act is up by half a voter.
11 years ago
Statistic: Preferred PM
• John Key – 65.2% (up 2.6)
• David Shearer – 12.4% (down 6.1)
Source: NZ Herald
Date: Wednesday Jun 26, 2013
Please excuse the double-dipping. Same article, different point.
“…preferred Prime Minister results are of decided voters only.”
There is no indication I could find as to how many of the 750 eligible voters polled were decided about the prefered PM. So as I understand it, this is in effect an unknown sample size. We have no idea how many voters the relevant percentages represent, other than that it is less than 750 (and presumably more than 100, since the percentages are shown to 1dp.)
Perhaps wiser heads than mine could comment on the impact (if any) this would have on the stated margin of error of plus or minus 3.6 per cent.
11 years ago
Statistic: Support disappears for convention deal
Source: New Zealand Herald
Date: 27 June 2013
This story states that “Public opinion has turned …” To justify this they quote statistics from surveys done in 1012 and 2103.
But the surveys are not comparable. They asked different questions.
The 2012 survey questions and results:
I disapprove 40.3%
I approve 19.6%
I conditionally approve 37.7%
The 2013 survey questions and results:
I disapprove 61.5%
I approve 33.8%
When the condition (that the number of pokie machines drops across the city) was removed from the 2013 survey those respondents had to switch to a new answer.
My guess is that most would have switched to “I disapprove” because their approval was conditional and the condition has now been removed. If so then the 2012 survey would have had results:
I disapprove 78.0%
I approve 19.6%
In that case public opinion has moved in the opposite direction to that in the headline.
Even if only half would have switched the figures would have been
I disapprove 59.2%
I approve 38.5%
and it still looks like the opposite to the headline.
The headline is pure fiction. The numbers don’t support it. The two surveys can’t be compared.
11 years ago
Statistic: Comparison of the number of children born in and out of wedlock.
Now: children born in wedlock number 1000 more than out of wedlock.
In 2000: ‘children born to unwed parents were outnumbered by more than seven to one.’
In 1980: ‘the gap was close to 30,000’.
Source: Dominion Post
Date: 17 July 2013
No base rate.
First, the shift from numbers of children to a ratio makes it impossible for the reader to compare now with 2000.
Secondly, the number of total children changed over the whole period. The analysis should account for the change.
11 years ago