EC255 Chapter Notes - Chapter 2: Frequency Distribution, Railways Act 1921
Document Summary
Also called raw data: grouped data. Frequency distributions: a frequency distribution is a list or table. Containing the values of a variable (or a set of ranges within which the data fall) And the corresponding frequencies with which each value occurs (or frequencies with which data fall within each range: summarize data to make it useful for interpretation. Histograms: the classes or intervals or bins are shown on the horizontal axis, frequency is measured on the vertical axis, bars of the appropriate heights used to represent number of observations within each class. Often answered by trial and error, subject to judgment. The goal is to create a distribution that is neither too jagged nor too blocky. Goal is to show pattern of variation in the data appropriately and meaningfully. How many class intervals: many (narrow class intervals) May yield very jagged distribution with lots of gaps. Poor indication of how frequency varies across classes.
