MATH-251 Lecture Notes - Lecture 2: Squared Deviations From The Mean, Standard Deviation, Variance
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Average middle values if n = even. If you have n observations, you want to know how spread out they are. Deviation from the mean of each data point is just x i - x n i=1. Sum of the deviations = equals zero. Notice that the sum of the deviations goes from 1 to n is equal to the sum of x i - the sum of x. The sum of x i - n (the sum of. The sum of x i - n ( x i ) n. Miles per gallon for a ford focus. This means that most ford focus cars are getting approximately 32. 7 mpg plus or minus ~5. 5 mpg. 1 n 1 i=1 (x i ) 2 + n 2 ] x. Lower fourth = median of the smallest half. Upper fourth = median of the largest half. Fourth spread = upper fourth - lower fourth.
