The mean will be larger than the median when the distribution is skewed toward the right. The median is the value where half of the observations are higher and half are lower. The mean is computed by just adding all the individual values together and dividing by the number of observations. When a distribution is skewed to the right, it means there are a few very large values that will increase the mean. Think about this set of values that has a rightward skew: 1, 2, 3, 4, 5, 1000, 1000. The median value is 4 because three values are lower (1,2,3) and three are higher (5, 1000, 1000). But the mean is much higher: 2015 divided by 7 = 287.9
