Chance News 55
Quotations
Populism, in its latest manifestation, celebrates ignorant opinion and undifferentiated rage. .... The typical opinion poll … doesn’t trouble to ask whether the respondent knows the first thing about the topic being opined upon, and no conventional poll disqualifies an answer on the ground of mere total ignorance. The premise of opinion polling is that people are, and of right ought to be, omni-opinionated – that they should have views on all subjects at all times – and that all such views are equally valid. …. So, given the prominence of polls in our political culture, it’s no surprise that people have come to believe that their opinions on the issues of the day need not be fettered by either facts or reflection. …. Now there’s the intellectual free lunch: I’m entitled to vociferous opinions on any subject, without having to know, or even think, about it.
We live in a world of real dangers and imagined fears. …. We are hounded by what I call “psycho-facts”: beliefs that, though not supported by hard evidence, are taken as real because their constant repetition changes the way we experience life. …. We act as if there’s a constitutional right to immortality and that anything that raises risk should be outlawed. ….
In a September 18 Statesman Journal story, “Ducks’ defense faces tough challenge”, a coach was quoted:
The only statistic that counts is winning and losing …. We don't get caught up in that. .... How many yards and those things.
Forsooths
Responding to a Canadian viewer who pointed out that "life expectancy in Canada under our health system is higher than the USA," Fox's Bill O'Reilly on 7/27/09 said,
Well, that's to be expected, Peter, because we have 10 times as many people as you do. That translates to 10 times as many accidents, crimes, down the line.
According to a September 18 FOX8 News WVUE-TV story, “Chance for rain”, this information was published in a cover story in an early 2009 bulletin of the American Meteorological Society.
[Researchers at the University of Washington] found people in Seattle didn't have much of a grasp for what the probability forecast [of rain] really means, but found the numbers helpful in planning their day.
Breaking News
The Wall Street Journal of September 8, 2009 reports on a study in the Journal of Bone and Joint Surgery: “The researchers compared the outcomes of patients who underwent surgery between 6 a.m. and 4 p.m. for fractures of the femur or tibia to those who had comparable surgeries for similar fractures outside those normal hours.”
| Sample | Reoperations Needed |
Sample Size |
Sample Proportion |
|
| Outside Normal Hours | 28 |
82 |
.3415 | |
| Within Normal Hours | 12 |
70 |
.1714 |
The results are:
Difference = p (1) - p (2) Estimate for difference: 0.170035 95% CI for difference: (0.0346494, 0.305420) Test for difference = 0 (vs not = 0): Z = 2.37 P-Value = 0.018
Fisher's exact test: P-Value = 0.026
Discussion
1. Why is the Fisher exact test P-Value (0.026) to be preferred to the other P-Value mentioned (0.018)?
2. The Wall Street Journal mentioned several caveats “making it difficult to determine the underlying reasons for the after-hours patients’ poor outcomes.” List a few practical significance hedges to the statistically significant result.
Contributed by Paul Alper
Amazon River at age 1,000,003 years
“Metrics mania: Are Americans too reliant on numbers?”
by John Yemma, The Christian Science Monitor, September 16, 2009
The author first reminds readers of an old joke:
A guy strikes up a conversation with another guy on a long plane flight to South America. They are over the Amazon.
Guy 1: “Did you know that the Amazon is 1,000,003 years old?”
Guy 2: “Really? How can you be so precise?”
Guy 1: “I was on this same flight three years ago, and a geologist told me the Amazon was a million years old.”
He then discusses the difficulty with “metrics-based management” efforts, but concludes, in a hopeful vein, with a formula and some encouragement:
Metrics + Grain of Salt = Somewhat Useful Information.
Still, even if we can’t trust data absolutely, we can extract meaning. We may not know how old the Amazon really is, but we know one thing for certain: It is three years older than when Guy 1 first flew over it.