ECO-2100 Lecture Notes - Lecture 3: Skewness, Frequency Distribution, Unimodality
Document Summary
Eco 2100 chapter three notes: a histogram is a graphical representation of a frequency distribution, the y-axis of a histogram shows the frequency or percentage (relative frequency) of each bin. Modal class: a histogram bar that is higher than those on either side. Modal classes may be artifacts of the way bin limits are chosen. Skewness: the direction of the longer tail of a histogram. Left skewed - (negatively skewed) a longer left tail. Right skewed - (positively skewed) a longer right tail. Symmetric - both tail areas are the same. Two ways to determine the skewness of the distribution of all data values in a sample. Mean: the mean is the balancing point, in excel, use the function average(data) Mean: median is very stable compared to mean, outliers change the value of the mean by much more than they change the median.
