Why do we need interpolation…..?

Why do we need interpolation…..?

•To approximate some quantity using information adjacent to it

      (constructing new data points using known data points)

•To make relationships between quantities using available information

   (fitting curves which satisfy known data points)

eg. Live births registered in Sri Lanka

(Census data:  www.statistics.gov.lk)

What would be the number of births in 1993 and 2002 ?Interpolation

What would be the number of births in 1990 and 2011 ?

Extrapolation