Cell membranes and transport: explain question

The fluidity of cell surface membranes can be measured using fluorescence recovery after photobleaching (FRAP). In an experiment, the lateral diffusion of a fluorescent lipid probe was measured in normal human red blood cell membranes and in membranes that had been treated to remove most of the cholesterol. The relative mobility of the probe (indicating membrane fluidity) was recorded at two temperatures:

(Values: higher number = greater fluidity)

Using your knowledge of the fluid mosaic model and the arrangement of cholesterol in cell surface membranes, explain the role of cholesterol in affecting membrane fluidity at different temperatures.