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Expectation and variance formulas Practice
Expectation, variance, and second-moment relationships.
Start practicingExpectation and variance formulas
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What you’ll practice
Expectation is a weighted centre; variance measures squared deviation from that centre. Track whether you are recalling a definition or a second-moment identity.
Where this helps
Describing the centre and spread of a random quantity.
Before you start
Use this topic to practice math you have already learned. The examples show the available kinds of recall tasks; this is not a complete textbook chapter. Check the answer form and any stated conditions.
Try a few examples
Real practice. Real progress.
Example 1 of 2
X has finite support x_1 through x_n with probabilities p_i that are nonnegative and sum to one.
Choose the exact expression.
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Start practicingExpectation and variance formulas
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