I needed to look up a formula for the estimating the relative efficiency to a completely randomized block design to a design without blocking.
A quick search on Google revealed the formula:
Here’s where I needed the formula. I was running a Monte Carlo simulation of three different statistical estimators. Each replication of the simulation required you to generate a binomial random variable with 100 trials and a probability of success of 0.5. You could just generate these values on the fly, but it makes sense to save the binomials that you used for one estimator and re-use the same ones for the other two estimators. This makes each replication in the Monte Carlo simulation a block, and you can estimate the precision that you have gained by the careful re-use of these binomials by fitting a completely randomized block design.
> tst.m1 <- lm(bb~trt+blk,data=mcd) > anova(tst.m1) Analysis of Variance Table Response: bb Df Sum Sq Mean Sq F value Pr(>F) trt 2 11.5617 5.7809 35659.326 < 2.2e-16 *** blk 999 2.2959 0.0023 14.176 < 2.2e-16 *** Residuals 1998 0.3239 0.0002 --- Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 > (999*0.0023+2000*0.0002)/(2999*0.0002)  4.497666
The re-use of the binomials has resulted in a 4.5 fold improvement in precision.
This formula was published in Experimental Design and Data Analysis for Biologists by Gerald Peter Quinn, Michael J. Keough, (ISBN: 9780521009768) and digitized by Google. There is a huge controversy over the Google project to digitize a whole bunch of books and make them accessible through their search engine. But I have to admit that I’m glad to have access to all those books for finding a formula like this.