Z-Scores, the Normal Curve and the 68-95-99.7 Rule
What a z-score measures, how to calculate one, the 68-95-99.7 rule for normal distributions, and how to compare scores from different tests.
Statistics & Probability
Mean, median, mode and standard deviation, probability rules, counting with permutations and combinations, and z-scores with the normal distribution.
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Permutations vs. Combinations: Does Order Matter?
The counting principle, factorials, permutations vs combinations with nPr and nCr, repeated letters, and probability with combinations, with worked examples.
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Probability Basics
Probability basics: complements, the addition and multiplication rules, conditional probability in two-way tables, counting and expected value.
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Mean, Median, Mode or Standard Deviation? Picking the Right Summary
How to find the mean, median, mode, range, quartiles and standard deviation, when each is the right summary, and how changing data affects them.