Thirty women were examined in a hospital by a doctor and the number of heart beats per minute were recorded and summarized as follows. Fine the mean heart beats per minute for these women, choosing a suitable method.
Given data is,
To find the class mark of each interval (xi), the following relation is used.
xi=Upper class limit+Lower class limit2
Class size, h of this data =3
Taking 75.5 as assumed mean (a), di and ui are calculated as follows.
From the table,
size of the class interval h=3.
Therefore, mean hear beats per minute for these women are 75.9 beats per minute.