ABSTRACT
The aim of this chapter is to explore the behavior of interval data. Because sometimes the points used for interpolation may not be exactly available and we may have some parts of the data. For this type of data, the word “approximately” is commonly used. Now, if we want to make the word approximately and about meaningful, one of the ways is to use the interval, for example, we show about 2 with an interval. So instead of about 2 or approximately 2, you can use a range that contains 2. Classification of interval data is possible in two ways. First, data whose length and width are intervals, and second, the data that only whose width is an interval. So, several methods for interpolating this interval data are explained in this chapter.
