Descriptive%20statistics

Descriptive%20statistics - (a) If y 1 = x 1 + c, y 2 = x 2...

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Descriptive Statistics Let x 1 , x 2 , . . . , x n be a sample. 1. Sample Mean ¯ x = x 1 + x 2 + . . . + x n n = n n =1 x i n 2. Sample Variance s 2 = ( x i - ¯ x ) 2 n - 1 = x 2 i - ( P x i ) 2 n n - 1 3. Sample standard deviation s = s 2 4. The average of all values in the population is called the population mean μ 5. When the population is finite and consists of N values, the population variance σ σ 2 = ( x i - μ ) 2 N 6. Some useful properties of s 2 Let x 1 , x 2 , . . . , x n be a sample and c be any nonzero constant
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Unformatted text preview: (a) If y 1 = x 1 + c, y 2 = x 2 + c, . . . , y n = x n + c , then s 2 y = s 2 x , and (b) If y 1 = cx 1 , y 2 = cx 2 , . . . , y n = cx n , then s 2 y = c 2 s 2 x 7. Describing Variation (Graphical methods) (a) Ordered Stem-and-leaf display (b) Histogram (c) Box plot (d) Time series plot (e) Pareto chart (f) Normal Probability plot 1...
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