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ExamsJEE MainMaths

Let \(\bar{x}\), \(M\), and \(\sigma^2\) denote the mean, mode, and variance, respectively, of the observations \(x_1, x_2, \ldots, x_n\). Define \(d_i = x_i - a\) for \(i = 1, 2, \ldots, n\), where \(a\) is any constant. Statement I: The variance of \(d_1, d_2, \ldots, d_n\) is \(\sigma^2\). Statement II: The mean and mode of \(d_1, d_2, \ldots, d_n\) are \(\bar{x} - a\) and \(M - a\), respectively.

  1. Both Statement I and Statement II are correct.
  2. Both Statement I and Statement II are incorrect.
  3. Statement I is correct, but Statement II is incorrect.
  4. Statement I is incorrect, but Statement II is correct.

Correct answer: Both Statement I and Statement II are correct.

Solution

The variance of a set of observations is unaffected by adding or subtracting a constant, so the variance of the new set remains C3. Additionally, both the mean and mode shift by the same constant, resulting in C3 and M being adjusted by -a.

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