Talk:Statistics/Basic: Difference between revisions
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(→Wrong emphasis in 'Extra'?: Apologies where due.) |
(→stddev slightly wrong: new section) |
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Hi Ledrug, I initially read the extra credit task as requiring the formula for calculating the standard deviation that avoids going once through the numbers to calculate the mean then going through the numbers a second time to work out the differences from the mean, and so on. Because that formula was ommited, it seemed like an attempt to make that part of the task about finding that formula as well as implementing it. If that was not your intent, and no-one else saw it that way then I apologise. --[[User:Paddy3118|Paddy3118]] 20:39, 2 July 2011 (UTC) |
Hi Ledrug, I initially read the extra credit task as requiring the formula for calculating the standard deviation that avoids going once through the numbers to calculate the mean then going through the numbers a second time to work out the differences from the mean, and so on. Because that formula was ommited, it seemed like an attempt to make that part of the task about finding that formula as well as implementing it. If that was not your intent, and no-one else saw it that way then I apologise. --[[User:Paddy3118|Paddy3118]] 20:39, 2 July 2011 (UTC) |
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== stddev slightly wrong == |
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Isn't the defintion of stddev <math>\sigma\equiv\sqrt{{1\over n-1}\sum_i \left(x_i - \bar x \right)^2}</math>? Ok, granted, the difference between this and what is currently posted on the task page is only numerically significant for small sample sizes, but if we are going to use the simplification for large sample sizes shouldn't we tone down the <math>\equiv</math>? --[[User:Rdm|Rdm]] 21:01, 2 July 2011 (UTC) |
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