Figure 2.

Correlation of fluorescence and cell size. Empiric cumulative distribution functions (ECDF) of fluorescence values for (a) perturbation and (b) phenotype showing their positive correlation with cell size. The fluorescence values were stratified into subsets corresponding to five quantiles (0-20%, 20-40%, 40-60%, 60-80%, and 80-100%) of cell size (forward light scatter), and the ECDF for each stratum was plotted in a different color. With increasing cell size, an increase in fluorescence values is also observed. (c) Regression line fitted to the data showing spurious correlation between the two parameters. In this case, the perturbation is known to cause no phenotype, and hence the correlation is considered to be artifactual. (d) After adjusting for cell size, the two parameters are uncorrelated.