Enter your data on a spread sheet. Important: Respect the convention for decimal points. It depends upon how your computer is configured, for commas or full stops.

These data come from an experiment where blood was mixed with different concentrations of sodium chloride solution. By the effect of osmosis the blood cells burst in dilute solutions but not in concentrated ones. When they burst the red blood cells released the red pigment haemoglobin into their surrounding solution. The amount of redness is measured by a colorimeter. The blood cells should be placed in physiological saline which is a specially prepared solution of sodium chloride in which the cells can survive best.

To draw a curve of these data, highlight the data and open the graphing menu and select scattergram (nuage de points). Do not select curves this is a recipe for disaster! The reason is that if you look at these data they are not at regular intervals (0, 0.1, 0.3, 0.5 etc.) and the curve plotting programme for some reason cannot cope with this, the scattergram program can.