This variation is assumed to be normally distributed ( although this assumption is not necessary for the theory to work ) around the desired average of 250 g , with a standard deviation , σ , of 2.5 g. To determine if the machine is adequately calibrated , a sample of `` n '' = 25 cups of liquid are chosen at random and the cups are weighed .
This variation is assumed to be normally distributed around the desired average of 250g , with a standard deviation of 2.5 g. To determine if the machine is adequately calibrated , a sample of `` n '' = 25 cups of margarine is chosen at random and the cups are weighed .