The Professor's Response

Professor, for number 7 in hw 10.1: after trying to get the SST I keep getting a negative value and i am not sure why?

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Professor McGukian

Hi Natalie,

First you would need to calculate the totals for each of the three columns: 40°, 80°, and 120°.  The sums for each of these columns of data are: 228.4, 168.5, and 81.9 respectively. Then we need to know the correction factor.

CF = (the sum of all of the observations)²/n = 478.8²/18 = 12,736.08

Then SST is given by: (sum for 40°)²/n1 + (sum for 80°)²/n2+ (sum for 120°)²/n3 - CF = 228.4²/6 + 168.5²/6 + 81.9²/6 - 12,736.08 = 1808.3233333.

Hopefully, that helps you find your error.

Professor McGuckian

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