Question

The length of 40 leaves of a plant are measured correct to one millimetre, and the obtained data is represented in the following table:
$\begin{array}{cc}\text{Length(in mm)}& \text{Number of leaves}\\ 118-126& 3\\ 127-135& 5\\ 136-144& 9\\ 145-153& 12\\ 154-162& 5\\ 163-171& 4\\ 172-180& 2\end{array}$
Convert given table into a continuous group frequency distribution.

Answer 1

It can be observed that the length of leaves is represented in a discontinuous class interval having a difference of 1 in between them. Therefore,$\frac{1}{2}=0.5$ has to be added to each upper class limit and also have to subtract 0.5 from the lower class limits so as to make the class intervals continuous.
$\begin{array}{cc}\text{Length (in mm)}& \text{Number of leaves}\\ 117.5-126.5& 3\\ 126.5-135.5& 5\\ 135.5-144.5& 9\\ 144.5-153.5& 12\\ 153.5-162.5& 5\\ 162.5-171.5& 4\\ 171.5-180.5& 2\end{array}$