Of a grade point average gpa the weights are the

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Unformatted text preview: 9 Frequency 8 17 12 8 7 4 2 4 2 6 Sample Mean for Grouped Data Rent ($) 420-439 440-459 460-479 480-499 500-519 520-539 540-559 560-579 580-599 600-619 Total fi 8 17 12 8 7 4 2 4 2 6 70 Mi 429.5 449.5 469.5 489.5 509.5 529.5 549.5 569.5 589.5 609.5 f iMi 3436.0 7641.5 5634.0 3916.0 3566.5 2118.0 1099.0 2278.0 1179.0 3657.0 34525.0 34,525 x 493.21 70 This approximation differs by $2.41 from the actual sample mean of $490.80. Variance for Grouped Data For Sample Data 2 f i ( Mi x ) s2 n 1 For Population Data 2 f i ( Mi m ) 2 N Sample Variance for Grouped Data Rent ($) 420-439 440-459 460-479 480-499 500-519 520-539 540-559 560-579 580-599 600-619 Total fi 8 17 12 8 7 4 2 4 2 6 70 Mi 429.5 449.5 469.5 489.5 509.5 529.5 549.5 569.5 589.5 609.5 Mi - x -63.7 -43.7 -23.7 -3.7 16.3 36.3 56.3 76.3 96.3 116.3 (M i - x )2 f i (M i - x )2 4058.96 32471.71 1910.56 32479.59 562.16 6745.97 13.76 110.11 265.36 1857.55 1316.96 5267.86 3168.56 6337.13 5820.16 23280.66 9271.76 18543.53 13523.36 81140.18 208234.29 continued Sample Variance for Grouped Data Sample Variance s2 = 208,234.29/(70 – 1) = 3,017.89 Sample Standard Deviation s 3,017.89 54.94 This approximation differs by only $.20 from the actual standard deviation of $54.74....
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This note was uploaded on 09/14/2013 for the course STAT 1001 taught by Professor Kim during the Fall '11 term at Yonsei University.

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