BIOL 3P96 Lecture Notes - Lecture 3: Interquartile Range, Standard Deviation, Quartile
23 Jul 2015
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Document Summary
Numerical data: location: where the observations are centered. Mean, median, and mode: spread: how variable the measurements are from individual to individual. Categorical data: proportion: the fraction of observations in a given category. Mean: most common metric to describe the location of a frequency distribution, average of a set of measurements. Standard deviation: most commonly used measure of distribution spread. Sample mean: average of the measurements in the sample, sum of all observations, divided by the number of observations. Calculating standard deviation: common measure of the spread of a distribution, indicates how different measurements typically are from the mean. Will be large if most observations are far from the mean, and small if most observations lie close to the mean. Standard deviation: standard deviation is calculated as the square root of variance. If frequency distribution is bell shaped, about two-thirds of observations lie within one standard deviation, and about 95% lie within two standard deviations.
