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FST Notes: Standard Deviation Vocabulary: 1. Standard Deviation- _________________________________________________________________________________________________ __________________________________________________ Symbol = _______________________________________________ 2. Variance- _____________________________________________________________________________________________________________ 3. Population- __________________________________________________________________________________________________________ 4. Sample- ______________________________________________________________________________________________________________ * *As =0 gets bigger __________________________________________________ __________________________________________________ When is it Used? Weather: Maximum temperatures for two cities. May be the same temperature on a given day; however, coastal city will have a higher standard deviation than an inland city making less certainty for the inland city potential high temp. Finance: Standard deviation measures risk and uncertainty of future returns. Higher standard deviation of closing prices yields less certainty for potential investments. Formula: Example: Sam has 20 rose bushes. The number of flowers on each bush is: 9, 2, 5, 4, 12, 7, 8, 11, 9, 3, 7, 4, 12, 5, 4, 10, 9, 6, 9, 4 Find the standard deviation. 1. = mean of all values