Measures of Dispersion for Grouped Data

7.2 Measures of Dispersion (Introduction)   (A) Determine the range of a set of data 1. For an ungrouped data, Range = largest value – smallest value. 2. For a grouped data, Range = midpoint of the last class – midpoint of the first class. Example 1: Determine the range of the following data. (a) 720, 840, 610, … Read more

7.1.4 Cumulative Frequency Cumulative Frequency of a data or a class interval in a frequency table is obtained by determining the sum of its frequency with the total frequencies of all its previous data or class interval.   (A) Ogive Ogive is a cumulative frequency graph which is obtained by plotting the cumulative frequency against … Read more

7.1.3 Frequency Polygons   1. A frequency polygon is a line graph that connects the midpoints of each class interval at the top end of each rectangle in a histogram.   2. A frequency polygon can be drawn from a (a) Histogram, (b) Frequency table   3. Steps for drawing a frequency polygon: Step 1: Add a … Read more

7.1.2 Histograms   (A) Draw a histogram based on the frequency table of a grouped data   1. A histogram is a graphical representation of a frequency distribution. 2. A histogram consists of vertical rectangular bars without any spacing between them. 3. Steps for drawing a histogram (a) Determine the lower boundaries and upper boundaries … Read more

7.1.1 Class Interval 1. Data that consist of the measurement of a quantity can be grouped into few classes and the range of each class is known as the class interval.     (A) Class Limits and Boundaries   Lower Limit and Upper Limit 2. For class interval, for example 30 – 39, the smaller value … Read more