Multiple choice

Class 10-20 20-30 30-40 40-50 50-60 60-70 70-80 Frequency 180 $f_1$ 34 180 136 $f_2$ 50 If the total frequency is $685$ and median is $42\dfrac{7}{12}$ then the missing frequencies are

  1. $81, 24$
  2. $80, 25$
  3. $82, 23$
  4. $83, 22$
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A Correct answer
AI explanation

The total frequency is 685, so the median class is the one containing the 342.5th observation, which falls in the 40-50 interval. Using the median formula, 42 7/12 = 40 + 10 * (342.5 - (180 + f1 + 34 + 180)) / 180, which simplifies to 25/60 = (342.5 - 394 - f1) / 180, yielding f1 = 81. Using the total frequency equation 680 + f1 + f2 = 685 gives f2 = 24.

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