Multiple choice

Marks 10-20 20-30 30-40 40-50 50-60 Frequency 4 10 20 40 50 The following frequency distribution showing the marks obtained by $124$ students in Economy at a certain school. Find the arithmetic mean using direct method.

  1. $50$ marks
  2. $80$ marks
  3. $30$ marks
  4. $45$ marks
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Midpoints (x): 15, 25, 35, 45, 55. Frequencies (f): 4, 10, 20, 40, 50. Sum(f) = 124. Sum(fx) = (4*15) + (10*25) + (20*35) + (40*45) + (50*55) = 60 + 250 + 700 + 1800 + 2750 = 5560. Mean = 5560 / 124 = 44.83, which rounds to 45.

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