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# Topic01 - Topic 1 Descriptive Statistics 1.1 Frequency Distribution a grouping of data into different categories showing the number of observations

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Unformatted text preview: Topic 1 Descriptive Statistics 1.1 Frequency Distribution : a grouping of data into different categories showing the number of observations in each class. Four steps: ● Decide on the number of classes. ● Determine the class interval or width. ● Set the individual class boundaries ● Tally the data into the classes and count the number of items in each.. Example Sort raw data in ascending order: 12, 13, 17, 21, 24, 24, 26, 27, 27, 30, 32, 35, 37, 38, 41, 43, 44, 46, 53, 58 ● Find range: 58 - 12 = 46 (Range=(max-min)) ● Select number of classes: 5 (Any number you desire ) ● Compute class interval (width): 10 (46/5 then round up) ● Determine class boundaries (limits): 10, 20, 30, 40, 50, 60 ● Compute class midpoints: 15, 25, 35, 45, 55 ● Count observations & assign to classes Class 10 but less than 20 15 3 20 but less than 30 25 6 30 but less than 40 35 5 40 but less than 50 45 4 50 but less than 60 55 2 Frequency Class Midpoint Histogram: Daily High Temperature 1 2 3 4 5 6 7 5 15 25 35 45 55 65 Frequency Frequency Polygon: Daily High Temperature 1 2 3 4 5 6 7 5 15 25 35 45 55 65 Frequency 1.2 Central Tendency1....
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## This note was uploaded on 09/15/2008 for the course ISMT 111 taught by Professor Wanxuhu during the Fall '08 term at HKUST.

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Topic01 - Topic 1 Descriptive Statistics 1.1 Frequency Distribution a grouping of data into different categories showing the number of observations

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