A Matter of Normalization

It is quite usual in toxicology to normalize an experimental signal of controls to 1 or 100. It makes the results independent on the particular conditions of experiment itself, and has the advantage to eliminate the inter-experiment variability on the control signal. Let me do it practically with our data, starting from experiment 1. The original data in excel:



Let's calculate the mean of C for experiment 1: 62. Therefore, we can divide all the values relative to experiment 1 by 62. At the same time, we will divide experiment 2 by 72.6 and experiment 3 by 83.6, obtaining the normalized database in figure, when N indicates the normalization:



We have some obvious consequences: the mean of CN is 1 for each experiment. The mean of CN1-CN2-CN3-CN4 indicates a relative fractional increase of effect. We will use the normalized data in further simulations.