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2 years ago

The random variable X takes on the values of 2, 5, n, and 15. The probability distribution of X is shown in the following table

Mathematics

2 answers:

iVinArrow [24]2 years ago

7 0

Answer:

Step-by-step explanation:

I did it on College Board

Marina86 [1]2 years ago

6 0

The question is missing some parts. Here is the complete question.

The random variable X takes on the values of 2, 5, n and 15. The probability distribution of X is shown in the table below.

The expected value of X is 9.1. What is the value of n?

a) 8

b) 8.52

c) 10

d) 12

e) 14.4

Answer: d) 12

Step-by-step explanation: In a probability distribution, Expected Value is the average (or mean) value a distribution can assume.

The Expected Value, E(X), can be determine by:

$E(X)=\Sigma xP(x)$

in which

x is how many times an event happens

P(x) is the probability of an event happening

The table below n is x and expected value is 9.1, then:

$9.1=2*0.1+5*0.4+0.2n+15*0.3$

$9.1=0.2n+6.7$

$0.2n=2.4$

n = 12

Value of n in this probability distribution is 12.

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Answer:

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Step-by-step explanation:

If we draw a square from the center of the large circle to the center of one of the small circles, we can see that the sides of the square are equal to the radius of the small circle (see attached diagram)

Let r = the radius of the small circle

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$\implies c=\sqrt{2r^2}$

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$\implies 2r^2=1-2r+r^2$

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$\implies r=\dfrac{-2\pm\sqrt{2^2-4(1)(-1)}}{2(1)}$

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