Biostatistics - The Carter Center

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Biostatistics The coefficient of variation is most useful in comparing the variability of several different samples, each with different means. This is because a higher variability is usually expected when the mean increases, and the CV is a measure that accounts for this variability. The coefficient of variation is also useful for comparing the reproducibility of different variables. CV is a relative measure free from unit of measurement. CV remains the same regardless of what units are used. In general, since CV is a pure number (a dimensionless quantity) it is suited for purposes of comparison. Example: a) Compute the CV for the birth weight data when they are expressed in either grams or ounces. Solution: in grams Χ = 3166.9 g, S = 445.3 g, 445.3 CV=100% × S = 100 % × = 14.1% Χ 3166.9 If the data were expressed in ounces, Χ =111.71 oz, S=15.7 oz, then 15.7 CV = 100% × S = 100 % × = 14.1% Χ 111.71 79
Biostatistics b)The following data were obtained from the summary results of 10 male medical students and the serum uric acid levels of 267 healthy males. Type of variable mean Standard deviation Pulse rate (beats/minute) 68.7 8.67 Serum uric acid level (mg per 100ml) 5.41 1.03 8.67 CV (pulse rate) = x 100% = 12.6% 68.7 1.03 CV (serum uric acid level) = x 100 % = 19% 5.41 Hence, the serum uric acid levels are relatively more spread out than pulse rates. Exercises 1. Define arithmetic mean, median, mode and geometric mean and explain their strengths and limitations. 2. Define range, variance and standard deviation and explain their advantages and disadvantages. 3. When values of the three measures of central tendency (mean, median and mode) of a certain distribution are equal, this distribution is said to be __________ . 80
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LECTURE NOTES Biostatistics For Hea
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Acknowledgments The development of
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UNIT FOUR: Demographic Methods.....
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Biostatistics questions, most of th
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Biostatistics Characteristics of st
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Biostatistics 1. It presents facts
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Biostatistics The functions/uses of
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Biostatistics UNIT TWO Collection o
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Biostatistics that an individual po
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Biostatistics Ordinal Data:- have o
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Biostatistics The secondary data ca
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Biostatistics measurements, sophist
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Biostatistics the questionnaire, as
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Biostatistics Checklist - is a list
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Biostatistics UNIT THREE Methods Of
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Biostatistics - The Carter Center

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