Multiple choice

A class teacher has the following absentee record of 40 students of a class for the whole term. Find the mean number of days a student was absent. No. of days 0-6 6-10 10-14 14-20 20-28 28-38 38-40 No. of students 11 10 7 4 4 3 1

  1. 12.475

  2. 12.405

  3. 12.005

  4. 12.950
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A Correct answer
Explanation

Calculate midpoints (x) and multiply by frequency (f). Sum(f*x) / Sum(f). Midpoints: 3, 8, 12, 17, 24, 33, 39. f*x: 33, 80, 84, 68, 96, 99, 39. Sum(f*x) = 499. Sum(f) = 40. Mean = 499/40 = 12.475.

AI explanation

Using the direct method for calculating the mean of grouped data, multiply each class mark by its frequency and sum the results. The class marks are 3, 8, 12, 17, 24, 33, and 39, yielding products of 33, 80, 84, 68, 96, 99, and 39. The sum of these products is 499, and dividing by the total of 40 students gives a mean of 12.475.

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