A normal distribution describes the shape of a continuous variables’ distribution. Normally distributed variables have a symmetrical and bell-shaped curve. The values of most of the data cluster around the mean at the peak of the curve, and fewer values appear as you move further away from the mean towards the tails. In a perfectly normal distribution, half of the scores will fall to the right of the mean, and half of the scores will fall to the left. Furthermore, 68% of the scores will fall within one standard deviation of the mean, 95% will fall within 2 standard deviations and 99.7% will fall within 3 standard deviations. This is called the empirical rule.