Statistics

Mike the Mad Biologist

Category archives for Statistics

The Real Flaw with Scratch Lottery Cards

Wired has a fascinating article about a statistician who figured how to beat the odds on the scratch-off lottery tickets–that is, pick cards that are more likely to produce winning combinations. And “more likely”, I mean getting it right up to 95 percent of the time. But the article mentions only in passing the real…

On Educational Metrics and Special Sandwiches

Over at Open Left, jeffbinnc pithily summarizes all of the metrics of which educational ‘reformers’ are fond: Then, to illustrate just how the focus on more and better tests is going to be raised to the levels of panacea, the CAP rolled out a new report last week that based just about everything on the…

At this point in Obama’s term, I’m simply hoping that the things I care about, like Social Security and education, aren’t mentioned by Obama in his State of the Union address. I’ve given up on thinking he’ll actually institute good policy (lost hope, if you will), and am just attempting a holding action. This is…

A couple of weeks ago, Jonah Lehrer wrote about the Decline Effect, where the support for a scientific claim often tends to decrease or even disappear over time (ZOMG! TEH SCIENTISMZ R FALSE!). There’s been a lot of discussion explaining why we see this effect and how TEH SCIENTISMZ are doing ok: PZ Myers gives…

A Dead Salmon: Bestest Control Experiment EVAH!

When analyzing data, understanding the limitations of your data is critical. One of the things we need to understand is significance: how strong does an effect have to be to considered not a result of random chance. Typically, we assume that if an effect has a five percent or less probability of occurring due to…

Robert Samuelson has a penchant for willingly misinterpreting data. Time was, the newspaper bidness considered that to be a bad thing. Given his track record on Social Security, which led me to create the Samuelson Unit, it should be no surprise whatsoever that Samuelson screws up educational data. Bob Somerby, rightfully offended by Samuelson’s false…

Not to pick on anyone, but this is what I go through with far too many projects: “My grant is due tomorrow. I just need to know….” And: “I can put you on my grant for a 0.5% FTE…”

Tuesday, I criticized the LA Times‘ use of the ‘value-added’ approach for teacher evaluation. There were many good comments, which I’ll get to tomorrow, but Jason Felch of the LA Times, pointed me to the paper describing the methodology. I’m not happy with the method used.

The LA Times has taken upon itself to rate school teachers in Los Angeles. To do this, the LA Times has adopted the ‘value-added’ approach (italics mine): Value-added analysis offers a rigorous approach. In essence, a student’s past performance on tests is used to project his or her future results. The difference between the prediction…

By way of Digby, I came across this poll of white attitudes towards various ethnicities (including whites) based on self-identified Tea Party support (note: respondents were only from four states, NV, MO, GA, and NC). One of things that struck me while looking at the data (pdf and pdf) was the extent to which whites…