STATS 2B03 Chapter Notes - Chapter 2: Frequency Distribution, Cumulate Rock, Exploratory Data Analysis
19 Jun 2013
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Main purpose in grouping data is summarization, making it easier to determine the nature of the information. Class intervals: set of contiguous, nonoverlapping intervals such that each value in the set of observations can be placed in only one interval. There should be no fewer than 5 intervals and no more than 15. Sturges"s rule: k = 1 +3. 322(log10n) 9, where k stands for the number of class intervals and n is the number of values in the data set. Class interval width: w = r/k, where r is the difference between the smallest and the largest observation in the data set. Frequency distribution: shows the way in which the values of the variable are distributed among the specified class intervals. Relative frequency of occurrence: proportion of values falling within a class interval. Relative frequencies: proportion of values falling within a particular class interval. Cumulate: sum the frequency or relative frequency of values within two or more contiguous class intervals.
