Categories
Statistics in the media

Survivorship Bias: Ultramarathoners suffer injuries but most may be minor, a study finds

A study of 396 ultramarathoners found that while many suffer injuries throughout the course of their race, the vast majority of them are minor. Researchers looked at medical data on runners who competed in Racing the Planet 4 Deserts series, a four-part ultra-race that takes place over seven days in rough terrain on four continents. Runners travel 150 miles per race.

What group of people is this study excluding?  Right, all the people who got injured training, and all the people who have quit running.  To really make the point, it also does not include people who possibly died from running.  This is a blatantly flawed study.

Ultramarathoners suffer injuries but most may be minor, a study finds

Categories
Statistics in the media

Supply, Demand and Marriage

They appear, for example, to focus more critically on the earnings potential of prospective mates. Because house size is often assumed to be a reliable signal of wealth, a family can enhance its son’s marriage prospects by spending a larger fraction of its income on housing.

For example, when Shang-Jin Wei, an economist at Columbia University, and Xiaobo Zhang of the International Food Policy Research Institute examined the size distribution of Chinese homes, they found that families with sons built houses that were significantly larger than those built by families with daughters, even after controlling for family income and other factors. They also generally found that the higher a city’s male-to-female ratio, the bigger the average house size of families that have sons.

Mr. Wei reports that many families with sons have begun to add a phantom third story to their homes, one that looks normal from the outside but whose interior space remains completely unfinished.

“Marriage brokers are familiar with the tactic,” he reports, “yet many refuse to schedule meetings with a family’s son unless the family house has three stories.”

Supply, Demand and Marriage

Categories
Statistics in the media

Does impatience make us fat?

Here is a good example of having to control for variables, in an attempt to best isolate the 2 factors being compared.

They controlled for other factors that might come into play, such as demographics and financial characteristics.

With everything else held constant, the researchers found that impatient individuals are more likely to be obese than people who are good at waiting. “We controlled for basically every variable in the kitchen sink,” says Courtemanche, the lead author and a professor at the University of Louisville. “It seems if you genuinely hold all else constant, the more patient you are, the less you weigh.”

 

Does impatience make us fat?

Categories
Statistics in the media

Correlation: Life Expectancy vs. # of Kids

Animating the scatterplot adds a 3rd dimension:  Time.  Also, his commentary reminds me of a horseracing announcer!