Category Archives: Sharing Stuff

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Bayes Thereom – broken down


To arrive at an understanding of Bayes Theorem, we begin with the

Definition of a conditional probability

P(A|B) = translates to “The probability of A happening, given that event B has occurred”.

P(A|B) can be rewritten like

P(A | B) = P(A ∩ B)

                ————

                   P(B)

 

Also, P(A ∩ B) = P(A | B) × P(B) (i.e. the probability of A and B).

And because P(A ∩ B) = can also be expressed as P(B ∩ A)

We can say  P(B ∩ A) = P(B | A) × P(A)

Therefore, we can also express “the probability of A happening given event B” as

P(A | B) = P(B | A) × P(A)

                ——————–

                       P(B)

 

We can further expand the probability of B by writing it as

P(B) = P(A) × P(B | A) + P(Al) × P(B | Al )

(in normal language, the probability of B is equal to the probability of A multiplied by the probability of A given B, plus the probability of the complement of A multiplied by the probability of the complement of A given B)

 

Thus resulting in the Law of Total Probability.  

This law enables us to find the total probability of a particular event based on conditional probabilities.  Also, our new expression can be substituted into our formula for “the probability of A happening given event B” as the denominator to give us Bayes Theorem.

Bayes Theorem provides a means of finding reverse conditional probabilities when you don’t know every probability up front.

 

Bayes Theorem

P(A | B) =                     P(A) × P(B | A)

                     ——————————-

                      P(A) × P(B | A) + P(Al) × P(B | Al)

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List of Built in Functions in Python


To get a list of built in functions in Python, type the following:

It will result in a list like the one below

 

 

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Talend Data Integration – Exception in component tOracleOutput_1java.sql.SQLException: ORA-01727: numeric precision specifier is out of range (1 to 38)


When you receive an out of range (1 to 38) error while importing from one Oracle DB to another Oracle DB

  1. Go to your tMap
    tMap
  2. Locate Big Decimals and any other precision numeric values.
  3. Be sure to fill in blanks.
  4. Save your job and re-run

Fin (I hope)

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