10. Exercise Problem IV

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

 

Number of hearbeats per minutes	\(65-68\)	\(68-71\)	\(71-74\)	\(74-77\)	\(77-80\)	\(80-83\)	\(83-86\)
Number of women	\(2\)	\(4\)	\(3\)	\(8\)	\(7\)	\(4\)	\(2\)