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AP EAMCET · Maths · Statistics

The following data represents the frequency distribution of 20 observations
\(x_i\)34581011
\(f_i\)\(\alpha+2\)\((\alpha-1)^2\)4\(\alpha-1\)2\(\alpha\)
Then its mean deviation about the mean is

  1. A 3
  2. B 2.4
  3. C 2.7
  4. D 2.9
Verified Solution

Answer & Solution

Correct Answer

(C) 2.7

Step-by-step Solution

Detailed explanation

\(\sum f_i = 20 \Rightarrow (\alpha+2) + (\alpha-1)^2 + 4 + (\alpha-1) + 2 + \alpha = 20\) \(\alpha^2 + \alpha + 8 = 20 \Rightarrow \alpha^2 + \alpha - 12 = 0\) \((\alpha+4)(\alpha-3) = 0 \Rightarrow \alpha = 3\) (since frequencies must be non-negative)…
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