First you have to square the radius. So for this question you multiply 5x5. That makes 25. Then you multiply that with pi ( 3.14 ) and that makes 78.50. Next you multiply it by 9, that makes 706.5.

7 0

3 years ago

A market research team compiled the following discrete probability distribution, where X represents the number of automobiles ow

rodikova [14]

Answer:

The standard deviation of X is 0.7

Step-by-step explanation:

We are given the following distribution:

x: 0 1 2 3

P(x): 0.3 0.5 0.2 0.4

We have to find the standard deviation of X.

Formula:

$E(x) = \displaystyle\sum x_iP(x_i)\\\\E(x) =0(0.3) + 1(0.5) + 2(0.2) + 3(0.4)\\\\E(x) = 2.1\\\\E(x^2) = \displaystyle\sum x_i^2P(x_i)\\\\E(x^2) =0(0.3) + 1(0.5) + 4(0.2) + 9(0.4)\\\\E(x^2) = 4.9\\\\Var(x) = E(x^2) - (E(x))^2 = 4.9-(2.1)^2 = 0.49\\\\\sigma(x) = \sqrt{Var(x)} =\sqrt{0.49} = 0.7$

Thus, the standard deviation of X is 0.7

6 0

3 years ago