Statistics — Chapter Summary

The mean is the sum

The mean is the sum of all observations divided by the total number of observations. For grouped data, class marks are used as representative values b

The mean is found by using

The mean is found by using the formula x̄ = Σf_i x_i / Σf_i, where x_i are class marks and f_i are frequencies. It is the simplest method when the val

One class mark is chosen as

One class mark is chosen as an assumed mean a. Deviations are calculated using d_i = x_i - a, and the mean is found by x̄ = a + Σf_i d_i / Σf_i.

This method uses u_i = (x_i

This method uses u_i = (x_i - a)/h, where h is the class size. The mean is found by x̄ = a + h(Σf_i u_i / Σf_i). It is convenient when the deviations

Cumulative frequency is the running total

Cumulative frequency is the running total of frequencies. It is used to form less than type and more than type distributions and to find the median cl