# Consider the following discrete probability distribution. What is the probability that x equals 7?

## X 3 4 7 9 P(X) 0.22 0.17 ? 0.18

Feb 27, 2017

$P \left(X = 7\right) = 0.43$

#### Explanation:

The Probability Distribution of the Random Variable $X$, is

We know that for any Probability Distribution:

$\sum P \left(X = x\right) = 1$

Hence;

$P \left(X = 3\right) + P \left(X = 4\right) + P \left(X = 7\right) + P \left(X = 9\right) = 1$
$\therefore 0.22 + 0.17 + P \left(X = 7\right) + 0.18 = 1$
$\therefore 0.57 + P \left(X = 7\right) = 1$
$\therefore P \left(X = 7\right) = 0.43$