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VICMath MethodsQuick questions
Unit 2: Functions, calculus and probability
Quick questions on Discrete random variables, expected value and variance (VCE Maths Methods Unit 2)
4short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is confusing $E[X^2]$ with $ ^2$?Show answer
They differ by the variance.
What is forgetting probabilities must sum to $1$?Show answer
Check before computing.
What is treating $E[X]$ as a typical outcome?Show answer
It is the long-run average, not necessarily one of the observed values.
What is negative variance?Show answer
Variance is always non-negative; a negative result indicates a calculation error.
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