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Probability — Maths STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceMathsProbability1 Mark
Question
Choose the correct answer from the given four options.
$\text{X}$
 $1$
 $2$
 $3$
 $4$
$\text{P}(\text{X})$
 $\frac{1}{10}$
 $\frac{1}{5}$
 $\frac{3}{10}$
 $\frac{2}{5}$
For the following probability distribution E(X2) is equal to:
  1. 3.
  2. 5.
  3. 7.
  4. 10.
✓

Answer

  1. 10.

solution:

$\text{E}(\text{X}^2)=\sum\text{X}^2\text{P}(\text{X})$

$=1\cdot\frac{1}{10}+4\cdot\frac{1}{5}+9\cdot\frac{3}{10}+16\cdot\frac{2}{5}$

$=\frac{1}{10}+\frac{4}{5}+\frac{27}{10}+\frac{32}{5}$

$=\frac{1+8+27+64}{10}=10$

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