ACT Statistics and Probability - Complete Interactive Lesson
Part 1: Mean, Median, Mode
๐ Statistics Probability
Part 1 of 7 โ Mean, Median, Mode
Mean = sum/count; Median = middle value (sorted); Mode = most frequent.
Weighted average: multiply each value by its weight, then divide by total weight.
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Key Insight: Effect of adding/removing values: track the sum.
ACT Tip: Range = max - min.
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Part 2: Data Displays
Data Displays
Part 2 of 7 โ Data Displays
Bar graphs, histograms, line graphs, pie charts, stem-and-leaf plots.
Read axes labels and scales carefully.
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Key Insight: Box plots: min, Q1, median, Q3, max.
ACT Tip: Histograms show frequency distribution โ bars touch (no gaps).
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Part 3: Counting Principles
Counting Principles
Part 3 of 7 โ Counting Principles
Fundamental counting principle: if event A has m outcomes and B has n outcomes, together they have m ร n outcomes.
Tree diagrams help visualize sequential events.
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Key Insight: With replacement: probabilities stay the same.
ACT Tip: Without replacement: probabilities change (dependent events).
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Part 4: Basic Probability
Basic Probability
Part 4 of 7 โ Basic Probability
P(event) = favorable outcomes / total outcomes.
P(A or B) = P(A) + P(B) - P(A and B).
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Key Insight: P(A and B) = P(A) ร P(B|A).
ACT Tip: Complement: P(not A) = 1 - P(A).
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Part 5: Combinations & Permutations
Combinations & Permutations
Part 5 of 7 โ Combinations & Permutations
Permutation (order matters): nPr = n!/(n-r)!.
Combination (order doesn't matter): nCr = n!/[r!(n-r)!].
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Key Insight: Factorial: n! = n ร (n-1) ร ... ร 2 ร 1.
ACT Tip: ACT tip: ask "does order matter?" to decide which formula to use.
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Part 6: Problem-Solving Workshop
Problem-Solving Workshop
Part 6 of 7 โ Problem-Solving Workshop
Permutation (order matters): nPr = n!/(n-r)!.
Combination (order doesn't matter): nCr = n!/[r!(n-r)!].
Check Your Understanding ๐ฏ
Key Insight: Factorial: n! = n ร (n-1) ร ... ร 2 ร 1.
ACT Tip: ACT tip: ask "does order matter?" to decide which formula to use.
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Part 7: Review & Applications
Review & Applications
Part 7 of 7 โ Review & Applications
Permutation (order matters): nPr = n!/(n-r)!.
Combination (order doesn't matter): nCr = n!/[r!(n-r)!].
Check Your Understanding ๐ฏ
Key Insight: Factorial: n! = n ร (n-1) ร ... ร 2 ร 1.
ACT Tip: ACT tip: ask "does order matter?" to decide which formula to use.
Check Your Understanding ๐ฏ
Match the Concepts ๐