Math Problem Statement
Let X be a random variable with the following probability distribution value exit X -3 is 0.30 -2 is 0.15 -1 is 0.30 and zero is 0.25 find the variance var(x) of x
Solution
To find the variance of the random variable , we follow these steps:
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List the values of and their corresponding probabilities:
X & P(X) \\ \hline -3 & 0.30 \\ -2 & 0.15 \\ -1 & 0.30 \\ 0 & 0.25 \\ \end{array}$$ -
Calculate the expected value :
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Calculate :
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Calculate the variance :
So, the variance is .
Would you like any further explanation or details on this problem?
Relative Questions:
- How do you interpret the variance of a random variable?
- What is the significance of the expected value ?
- How does variance relate to standard deviation?
- Can variance be negative? Why or why not?
- How would the variance change if one of the probabilities in the distribution was increased?
- What are some common applications of variance in real-world scenarios?
- How is variance affected if all values of are multiplied by a constant?
- What happens to the variance if the distribution becomes more spread out?
Tip: When calculating the variance, remember that it measures the spread of the data around the mean, reflecting how much the values of the random variable deviate from the expected value.
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Math Problem Analysis
Mathematical Concepts
Probability Theory
Expected Value
Variance
Formulas
Variance formula: Var(X) = E(X^2) - (E(X))^2
Theorems
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Suitable Grade Level
Undergraduate
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