Summary

In this chapter, you have studied the following points:

1. The mean for grouped data can be found by :

(i) the direct method: = ∑f_i x_i∑f_i

(ii) the assumed mean method: = + ∑f_i d_i∑f_i

(iii) the step deviation method: = a +(∑f_i u_i∑f_i) ×

2. The mode for grouped data can be found by using the formula:

Mode = + f₁ - f₀2f₁-f₀-f₂ × h

where symbols have their usual meanings.

3. The cumulative frequency of a class is the frequency obtained by adding the frequencies of all the classes the given class.

4. The median for grouped data is formed by using the formula:

Median = + n2−cff × h (where symbols have their usual meanings)