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 72 students
Methods of calculation using a histogram
The estimate of the number of students who revised for less than 45
minutes is given by the area, A, 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 = 72 students
Learn more about histograms here:
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