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VICMath MethodsQuick questions
Unit 1
Quick questions on Probability and counting: VCE Math Methods Unit 1 Year 11
9short 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 the multiplication principle?Show answer
If an event can occur in $m$ ways followed by another in $n$ ways, the combined event can occur in $m \times n$ ways.
What is permutations?Show answer
A permutation is an arrangement of items in order. The number of ways to arrange $n$ distinct items in order is:
What is combinations?Show answer
A combination is a selection without regard to order. The number of ways to choose $k$ items from $n$ (order does not matter) is:
What is independence test?Show answer
Events $A$ and $B$ are independent if and only if $P(A \cap B) = P(A) \cdot P(B)$. Equivalently, $P(A | B) = P(A)$.
What is confusing permutations and combinations?Show answer
Permutations: order matters. Combinations: order does not.
What is forgetting the overlap?Show answer
$P(A \cup B) = P(A) + P(B) - P(A \cap B)$. Forgetting the subtraction double-counts.
What is conditional probability backwards?Show answer
$P(A | B)$ is generally not equal to $P(B | A)$. Bayes's theorem relates the two.
What is treating dependent events as independent?Show answer
Drawing without replacement: the second draw depends on the first. Always check whether sampling is with or without replacement.
What is misreading the question?Show answer
"At least one" usually means "1 - none". "Exactly one" is different from "at least one".