EC255 Lecture Notes - Lecture 3: Average Absolute Deviation, Level Of Measurement, Central Tendency
Document Summary
Numerical data properties: central tendency, location, variation, dispersion. Measures of central tendency: ungrouped data: provide information about the centre or middle part of a group of numbers, provide location information, mean, median, mode. Mode: the mode is the value that occurs most frequently, not affected by extreme values, used for either numerical or categorical data, there may be no mode, there may be several modes. Median: middle value in an ordered array of middle numbers, applicable for ordinal, interval, and ratio data, not applicable for nominal data, not affected by extreme values. Mean: the most common measure of central tendency, mean = sum of values divided by the number of values, extremely large or extremely small values impact the mean, not applicable for nominal or ordinal data. Mathematical notation: population: a population is the group of all items of interest (n, mean for population:
