ECON 2B03 Lecture Notes - Lecture 5: Descriptive Statistics, Kurtosis, Interquartile Range
Document Summary
Measures the typical squared deviation about the mean. Calculated by averaging the squares of individual deviations from the mean. In r we use the var() function (note: this computes sample variance) Falls in the same range of magnitude (and appears in the same units) as the observations themselves. *higher variance = more density about the mean (more dispersion)* In r we use the sd() function (note: this computes sample variance) Equals the difference between the largest and smallest observation in a data set (in r we could use the range() function) Measures differences between 2 values in the ordered array (called fractiles") Quartiles divide the array into 4 quarters. Interquartile range difference between the 3rd and 1st quartiles (contains the middle 50% of the data) In r we use the iqr() and quartile() functions. A frequency distribution"s degree of distortion from pearson"s (first) coefficient of skewness is (we want to know, is it +/-?)