Confused to find formula from this article (naive bayes)

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hello dear i saw this article to learning about naive bayes.
here is the article :

Naive Bayes Classifier[^]

so far i am understand the theory
but i cant understand how to get this RESULT

p(weight | male) = 5.9881e-06 <--- THIS RESULT
p(foot size | male) = 1.3112e-3 <--- THIS RESULT
posterior numerator (male) = their product = 6.1984e-09 <--- THIS RESULT

p(height | female) = 2.2346e-1 <--- THIS RESULT
p(weight | female) = 1.6789e-2 <--- THIS RESULT
p(foot size | female) = 2.8669e-1 <--- THIS RESULT
posterior numerator (female) = their product = 5.3778e-04 <--- THIS RESULT

wish someone explain to me step by step to get this result.
thank you dear,,

Posted 3-Dec-15 7:23am

Gun Gun Febrianza

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Comments

Suvendu Shekhar Giri 3-Dec-15 13:31pm

Just a suggestion: Ask the author. He might be able to give you exact explanation.

Gun Gun Febrianza 3-Dec-15 13:35pm

but he never respon the comments in his article.

BillWoodruff 4-Dec-15 10:12am

Did you download the source code for the article and compile it ?

2 solutions

Solution 1

Unfortunately, last time this user was seen was almost five years ago.

You may have to get back to the wikipedia article he is talking about, and get some clue about how values are computed. You may also study the source code of said article to catch how it works.

I have read the article, but could not explain it to you without having to go through the steps I described above.

Posted 3-Dec-15 10:04am

phil.o

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George Jonsson · Accepted Answer · 2015-12-03T16:50:00

The same formula is used for all the calculation

p(x) = 1/sqrt(2*PI*σ²) * exp(-(x - μ)²/2*σ²)

where
x is the sample value (length, weight or foot size)
μ is the mean value
σ² is the variance

So in numbers for the weight for the male it will be
x = 130
μ = 176.25
σ² = 122.92

p(weight|male) = 1/sqrt(2*PI*122.92) * exp(-(130 - 176.25)²/2*122.92) =
1/27.79 * exp(-8.70) = 5.9881E-6
(In reality I kept the values in the memory of the calculator, so if you use these values directly the result will differ a bit)

Then it is just a matter to do the same for the foot size
x = 8
μ = 11.25
σ² = 0.91667
p(foot|male) = 1/sqrt(2*PI*0.91667) * exp(-(8 - 11.25)²/2*0.91667) =
1/2.40 * exp(-5.76) = 1.3112E-3

And so on for the female.