# Thirty women were examined in a hospital by a doctor and the number of heart beats per minute were recorded and summarised as follows. Find the mean heart beats per minute for these women, choosing a suitable method.

## Solution :

Let assumed mean a = 75.5

Mean = a + $$\sum f_id_i\over \sum f_i$$ = 75.5 + $$12\over 30$$ = 75.5 + 0.4 = 75.9