Select and write the appropriate answer from the given alternatives in each of the following sub-questions:
Let the p.m.f of a random variable X be
$P (x) = \frac{3 - x}{10}$ for x = $- 1, 0, 1, 2 = 0$
otherwise
Then E(X) is _______.

1

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2

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0

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- 1

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Solution

The correct option is C $1$
$P (x), p m f = {\begin{matrix} \frac{3 - x}{10}, & x = - 1, 0, 1, 2 0, & o t h e r w i s e \end{matrix}$
$E (x) = P (- 1) + P (0) + P (1) + P (2)$
$E (x) = (\frac{3 + 1}{10}) + (\frac{3 - 0}{10}) + (\frac{3 - 1}{10}) + (\frac{3 - 2}{10})$
$E (x) = (\frac{4 + 3 + 2 + 1}{10})$
$E (x) = (\frac{10}{10})$
$E (x) = 1$

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Similar questions

X

P (x) = \frac{3 - x}{10}

x = - 1, 0, 1, 2

E (X)

$X = x$	$- 2$	$- 1$	$0$	$1$	$2$	$3$
$P (x)$	$0.1$	$0.1$	$0.2$	$0.2$	$0.3$	$0.1$

E (x) =

x

P (x) = ⎧ ⎪ ⎨ ⎪ ⎩ \begin{matrix} (\frac{4}{x}) {(\frac{5}{9})}^{x} {(\frac{4}{x})}^{4 - x}, x = 0, 1, 2, 3, 4 0, otherwise \end{matrix}

E (x)

(x)

X

P (x) = \frac{1}{5}

x = 1, 2, 3, \dots 14, 15;

P (x) = 0

E (X)

V a r (X)

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