The given frequency distribution is in inclusive form. So, first we convert it into exclusive form.
Now, consider the class 20-24, 25-29.
lower limit of 25-29 is 25.
Upper limit of 20-24 is 23.
Thus, the half of the difference is `(25-24)/2=1/2=0.5`
So, we subtract 0.5 from each lower limit and add 0.5 to each upper limit. The table for continuous grouped frequency distribution is given below.
Thus, the given data becomes in exclusive form. Along the horizontal axis, we represent the class interval of ages on some suitable scale. The corresponding frequencies of number of teachers are represented along the vertical axis on a suitable scale.
Since, the given intervals start with 19.5-24.5. It means that, there is some break indicated near the origin to signify the graph is drawn with a scale beginning at 19.5.
