EC255 Lecture Notes - Lecture 3: Square Root, Statistical Inference, Average Absolute Deviation
Document Summary
Provide information about the center or middle part of a group of numbers. Middle value in an ordered array of numbers. If there is an odd number of terms, the median is the middle term. If there is an even number of terms, the median is the average of the middle two terms. Sum of values divided by the number of values. Not applicable for nominal or ordinal data n=sample population. Used to indicate how much are the observations spread out around the mean. Average of the absolute deviations from the mean (no negative numbers) x x - m | x - m | 18 m = 13 x - m | x - m | Average of the squares of deviations from the mean x. = 13 x - ( x - )2. Nobody knows what a squared dollar is. Use the square root of the variance to have intuitive interpretation. This is the standard deviation: population standard deviation.
