The first step to create the histogram is to count the number of data that belong to each interval.
5, 9 and 2 belong to the first interval (1-10). The frequency of this interval is 3.
12 belongs to the second interval (11-20). The frequency of this interval is 1.
21 and 29 belong to the third interval (21-30). The frequency of this interval is 2.
32 and 38 belong to the fourth interval (31-40). The frequency of this interval is 2.
Create the histogram, that has to look like this.
It means that you have to drag the (1-10) bar to 3, the (11-20) bar to 1 and both (21-30) and (31-40) bars to 2.
