Computer the arithmetic of the following distribution.

Let’s convert the inclusive type of data into exclusive type. We can do this by subtracting 0.5 from each lower limits of the class intervals and by adding 0.5 to each upper limits of the class interval.

Using direct method, we can find arithmetic mean of the data.

Let’s make the following table for ease of calculation:

Mean is given by

⇒

⇒ Mean = 55.5

Thus, the arithmetic mean of the data is 55.5.