estimating percent effort

Many statisticians in American academic institutions have "soft money" appointments funded by a mutable portfolio of research grants. A fundamental aspect of holding such a position is proposing and negotiating "percent effort". We propose a few methods for percent effort estimation for use by soft money statisticians and scientists funding such statisticians.

exact and approximate probabilities for laundry socks problem

Karl Broman's Twitter picture with 11 different socks from his laundry sparked a spirited Twitter conversation. We derive exact and approximate formulas for the probability of no matching socks. If there are $$n$$ sock pairs and $$k$$ are chosen the probability of no match in $$k$$ socks is approximately $$\exp(-k^2/(4n))$$ when $$k/n$$ is small.

stata and r ranksum test p-values differ

Stata and R give different results for the Ranksum test, a widely-used non-parametric test. We investigate why that happens and make recommendations.

poisson approximations for laundry socks problem

We derive Poisson approximations for the problem using a connection with the famous birthday problem. The probability of no mathching sock if $$k$$ out of $$n$$ socks are chosen is of the form $$\exp(-c k^2/n)$$, where $$c$$ is a constant depending on sock drawer composition.

beer on tap in memphis

Places where beer is on tap in Memphis