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What is Standard detion is a measure of: and explain in detail?
The standard detion is the positive square root of variance and is used to measure the detion from the mean value. It gives the extent of spread of dispersion. Thus in simpler terms, the dispersion of values about the mean, is directly propoional to the standard detion. Ref: Fundamental Statistics for The Behavioral Sciences By David C. Howell, Pages 88-90; Park's Textbook of Social and Preventive Medicine, 19th Edition, Page 701