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ENME 392 - Homework 1 - Sp12_Solutions

# ENME 392 - Homework 1 - Sp12_Solutions - ENME392 Spring...

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1 ENME392 Spring 2012 Homework 1 Solutions Assignment: 1) (49pts) Using the dataset of exercise 1.1 in Walpole: 3.4, 2.5, 4.8, 2.9, 3.6, 2.8, 3.3, 5.6, 3.7, 2.8, 4.4, 4.0, 5.2, 3.0, 4.8 a) (7pts) What is the sample size? Sample size ( n ) = 15 b) (7pts) Calculate the sample mean Mean ( x ) = = n i i n x 1 , where x i is the i th sample and n is the number of samples. 79 . 3 15 8 . 4 0 . 3 2 . 5 0 . 4 4 . 4 8 . 2 7 . 3 6 . 5 3 . 3 8 . 2 6 . 3 9 . 2 8 . 4 5 . 2 4 . 3 = + + + + + + + + + + + + + + = x c) (7pts) Calculate the sample median Arranging the samples in ascending order (can be performed in Excel): 2.5, 2.8, 2.8, 2.9, 3, 3.3, 3.4, 3.6 , 3.7, 4, 4.4, 4.8, 4.8, 5.2, 5.6 Since n=15, which is odd; Median= x (n+1)/2 = x 8 = 3.6 d) (7pts) Calculate the sample standard deviation Standard deviation (s)= = n i i n x x 1 2 1 , where x i is the i th sample, n=15, and x =3.79 s = 0.97 e) (7pts) Calculate the sample variance Variance= s 2 =0.94 f) (7pts) Plot the data by way of a dot plot: x-axis: 1 = 0 - 1, 2 = 1.1 - 2, 3 = 2.1 - 3 and so on.

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