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AP EAMCET · Maths · Probability

If a cubical die is thrown, then the mean and variance of the random variable \(\mathrm{X}\), giving the number on the face that shows up, are respectively

  1. A \(\frac{2}{7}, \frac{12}{35}\)
  2. B \(\frac{7}{2}, \frac{12}{35}\)
  3. C \(\frac{1}{7}, \frac{1}{12}\)
  4. D \(\frac{7}{2}, \frac{35}{12}\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(\frac{7}{2}, \frac{35}{12}\)

Step-by-step Solution

Detailed explanation

\begin{aligned} & \text { } X=\{1,2,3,4,5,6\} \text { and } P(1)=P(2) \ldots P(6)=\frac{1}{6} \\ & \text { Mean }=\sum x_i \cdot P=\frac{1+2+3+4+5+6}{6}=\frac{21}{6}=\frac{7}{2} \\ & \text { Variance }=\sum x_i^2 \cdot P-(\text { Mean })^2 \\ &…