# Interpolation in nlp - definition of O term

Reading definition of interpolation below how are the O terms defined? Is this a value that is set manually?

# Example

• P( Sam | I am ) = count( Sam I am ) / count(I am) = 1 / 2

### Interpolation using N-grams

We can combine knowledge from each of our n-grams by using interpolation.

E.g. assuming we have calculated unigram, bigram, and trigram probabilities, we can do:

P ( Sam | I am ) = Θ1 x P( Sam ) + Θ2 x P( Sam | am ) + Θ3 x P( Sam | I am )

(original problem statement image)

• unigram, bigram and trigram probabilities? – ignatius May 10 '18 at 12:03

Terminology point: those symbols aren't O, but thetas Θ.