Introduction

If we are given a set of data points:
X 1 2 3 4 5 6 7 y 28 21 96 96 120 87 50  We know the value of y when x is a whole number, i.e. 1, 2, 3
 But when x is 1.5 we do not have a corresponding value for y.
 Interpolation is the method of estimating the value of y for a given x when we don't have a data point for it.