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Chpater 5 Typo #82

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rickiepark opened this issue Oct 13, 2018 · 3 comments
Open

Chpater 5 Typo #82

rickiepark opened this issue Oct 13, 2018 · 3 comments
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fixed-in-3rd-edition Tagged as fixed in the upcoming 3rd edition

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@rickiepark
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(p159) In first Eq., \Sigma_i = \frac{1}{n_i} S_W should be \Sigma_i = \frac{1}{n_i} S_i

@rickiepark
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(p159) In first code box, It's not critical but it's better to use np.cov(..., bias=True). By default, np.cov() use \frac{1}{n-1} not \frac{1}{n}. :)

@rickiepark
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(p170) In last sentence, \gamma = \frac{1}{2 \sigma} should be \gamma = \frac{1}{2 \sigma^2}

@rasbt
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rasbt commented Jun 16, 2019

(p159) In first Eq., \Sigma_i = \frac{1}{n_i} S_W should be \Sigma_i = \frac{1}{n_i} S_i

Hm, in my version this already looks correct. I think we fixed that in a reprint in the past already.

(p159) In first code box, It's not critical but it's better to use np.cov(..., bias=True). By default, np.cov() use \frac{1}{n-1} not \frac{1}{n}. :)

Hm, I'd say ideally we want n-1 but it probably won't make a big difference in practice.

(p170) In last sentence, \gamma = \frac{1}{2 \sigma} should be \gamma = \frac{1}{2 \sigma^2}

Thanks!

@rasbt rasbt added the fixed-in-3rd-edition Tagged as fixed in the upcoming 3rd edition label Jun 16, 2019
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