Month: March 2014

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Can women be professors or doctors? Not according to Jet Airways

gshmueli

I am already used to the comical scene at airports in Asia, where a sign-holder with “Professor Galit Shmueli” sees us walk in his/her direction and right away rushes to my husband. Whether or not the stereotype is based on actual gender statistics of professors in Asia is a good question. What I don’t find amusing is when a corporate like Jet Airways, under the guise of “celebrating international women’s day“, follows the same stereotype. When I tried to book a flight on Jetairways.com, it would not allow me to use the Women’s Day discount code if I chose title … Continue reading Can women be professors or doctors? Not according to Jet Airways

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The use of dummy variables in predictive algorithms

gshmueli

Anyone who has taken a course in statistics that covers linear regression has heard some version of the rule regarding pre-processing categorical predictors with more than two categories and the need to factor them into binary dummy/indicator variables: “If a variable has k levels, you can create only k-1 indicators. You have to choose one of the k categories as a “baseline” and leave out its indicator.” (from Business Statistics by Sharpe, De Veaux & Velleman) Technically, one can easily create k dummy variables for k categories in any software. The reason for not including all k dummies as predictors in a … Continue reading The use of dummy variables in predictive algorithms