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sattari [20]
3 years ago
9

Suppose that the probabilities are 0.4, 0.3, 0.2, and 0.1, respectively, that 0, 1, 2, or 3 power failures will strike a certain

subdivision in any given year. Find the mean and variance of the random variable X representing the number of power failures striking this subdivision.
Mathematics
1 answer:
defon3 years ago
7 0

Answer:

mean = 1 power failure

variance = 1 (power failure)²

Step-by-step explanation:

Since the mean is computed as

mean = E(x) = ∑ x * p(x) for all x

then for the random variable x=power failures , we have

mean = ∑ x * p(x) = 0 * 0.4 + 1* 0.3 + 2*0.2 + 3* 0.1 = 1 power failure

since the variance can be calculated through

variance =  ∑[x-E(x)]² * p(x) for all x

but easily in this way

variance = E(x²) -  [E(x)]² , then

E(x²) = ∑ x² * p(x) = 0² * 0.4 + 1²* 0.3 + 2²*0.2 + 3²* 0.1 = 2 power failure²

then

variance = 2 power failure² - (1 power failure)² = 1 power failure²

therefore

mean = 1 power failure

variance = 1 power failure²

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Step-by-step explanation:

W=-6, x=1.2, and z=-6/7

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we substitute

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3 years ago
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irinina [24]

Answer:

3 hours every weekday

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Rhett made $250 washing cars with his mobile car wash company. He charges $70 per car and earned $50 in tips. Write an equation
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250=

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3 0
3 years ago
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a card player selects a playing card from a well-shuffled deck of standard playing cards and sees if the card is a red card or n
DIA [1.3K]

It is not binomial random variable , since the number of red cards is unknown in the deck of cards in the starting of experiment.

As given in the question,

Number of cards are unknown.

Number of red cards are unknown in the starting of experiment.

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For binomial random variable number of red cards should be known.

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3 years ago
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