Multiple choice

For a frequency distribution, $\sum {{f_i}{u_i} = - 50,}$ $n = 100,$ $c = 10$ and $\overline x = 25,$ then assumed mean $A$= _____

  1. $30$
  2. $20$
  3. $40$
  4. $50$
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A Correct answer
Explanation

Mean formula: x_bar = A + (sum(fi*ui)/n) * c. 25 = A + (-50/100) * 10. 25 = A - 5. A = 30.

AI explanation

Using the step deviation method formula, the mean is calculated as A plus c times the sum of f_i u_i divided by n. We substitute the given values to get 25 = A + 10 times (-50 divided by 100), which simplifies to 25 = A - 5. Solving this equation yields an assumed mean A of 30.

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