Statistical Sciences 2035 Chapter Notes - Chapter 2.1-2.2: Abscissa And Ordinate, Frequency Distribution, Cumulative Frequency Analysis
6 Oct 2017
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Summary of data presented in the form of class intervals and frequencies. When creating a frequency distribution, researcher should determine the range and he raw data. Also need to determine how many classes it will contain. One guideline is to select between 5 and 15 classes. Then need to determine the width of the class interval. Approximation of class width is calculated by dividing range by the # of classes. Midpoint of each class interval is called the class midpoint, aka class mark. The value halfway across the class interval and can be calculated as the average of the two class endpoints. Midpoint of the class interval 3-8 is (5. 5) Class midpoint is important because it becomes the representative value for each class in most group calculations. Is the proportion of the total frequency that is any given class interval in a frequency distribution. Individual class frequency divided by the total frequency.
