The frequency of revision times is given by the product of the frequency
density value and the class width.
Correct response:
- The number of students are <u>72 students</u>
<h3>Methods of calculation using a histogram</h3>
The estimate of the number of students who revised for less than 45
minutes is given by the area, <em>A,</em> under the histogram to the left of the 45
minute mark as follows;
Frequency, f = Frequency density × Class width
Number of students = ∑f
Therefore;
A = 5 × 2 + 10 × 2.2 + 20 × 1.6 + 10 × 0.8 = 72
- The number of students that revised for less than 45 minutes = <u>72 </u>students
Learn more about histograms here:
brainly.com/question/17139138
