Panel A shows a line graph of mean cell volume in femtoliters (fL) against time relative to the switch in hours. Panel B shows a line graph of the coefficient of variation (CV) of cell volume against the same time scale. Panel C and D repeat the same measurements as Panel A and B but exclude one outlier position. Panel E shows a line graph of the total number of pooled cells per frame against time since the nutrient switch. Panel F is a microscopic image of the first frame of the outlier position excluded from Panels C and D, with black lines showing cell contours. The shaded areas in the graphs represent the standard error obtained from bootstrapping with 1000 iterations and replacement. The photo includes a scale bar of 10 micrometers.
Average behavior of a cell population, as calculated from single-cell measurements during the nutrient switch, is robust to outliers. However, measures of variability are sensitive to them. (A and B) Mean cell volume (fL) and (B) CV of cell volume are plotted against time relative to the nutrient switch (hours). Bootstrapping with 1,000 iterations and replacement was used to obtain the standard error represented by shaded areas. The dataset for A and B includes all positions from three independent microscopy experiments. (C and D) In C and D, one outlier position with one very large cell at the beginning of the experiment is excluded from the dataset and the mean cell volume and CV of cell volume are recalculated. (E) Total number of pooled cells per frame is plotted against the time since the nutrient switch. (F) First frame of the outlier position excluded from the analysis in C and D is shown with black lines showing cell contours.