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Math Formula Encyclopedia

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134 formulas10 subjectsExamples + variables
AllAlgebra 16Arithmetic 8Calculus 15Everyday Math & Conversions 7Finance & Business 9Geometry 28Number Theory & Sequences 8Science & Engineering 16Statistics & Probability 16Trigonometry 11

16 matching formulas

Statistics & Probability

Population Mean

μ = Σx / N

Arithmetic mean of an entire population.

Open formula →Statistics & Probability

Sample Mean

x̄ = Σx / n

Arithmetic mean of a sample.

Open formula →Statistics & Probability

Population Variance

σ² = Σ(x−μ)²/N

Average squared deviation from the population mean.

Open formula →Statistics & Probability

Sample Variance

s² = Σ(x−x̄)²/(n−1)

Unbiased estimator of population variance.

Open formula →Statistics & Probability

Standard Deviation

σ = √σ²

Square root of variance.

Open formula →Statistics & Probability

Z-Score

z = (x−μ)/σ

Standardizes a value by distance from the mean in standard deviations.

Open formula →Statistics & Probability

Combination

C(n,r)=n!/[r!(n−r)!]

Counts unordered selections without replacement.

Open formula →Statistics & Probability

Permutation

P(n,r)=n!/(n−r)!

Counts ordered selections without replacement.

Open formula →Statistics & Probability

Basic Probability

P(E)=favorable outcomes/total outcomes

Probability for equally likely outcomes.

Open formula →Statistics & Probability

Complement Rule

P(Eᶜ)=1−P(E)

Probability that an event does not occur.

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Addition Rule

P(A∪B)=P(A)+P(B)−P(A∩B)

Probability that A or B occurs.

Open formula →Statistics & Probability

Multiplication Rule

P(A∩B)=P(A)P(B|A)

Probability that both events occur.

Open formula →Statistics & Probability

Binomial Probability

P(X=k)=C(n,k)p^k(1−p)^(n−k)

Probability of exactly k successes in independent Bernoulli trials.

Open formula →Statistics & Probability

Expected Value

E[X]=ΣxP(x)

Long-run probability-weighted average outcome.

Open formula →Statistics & Probability

Standard Error of Mean

SE=σ/√n

Common reference identity or relationship used in statistics & probability.

Open formula →Statistics & Probability

Correlation Coefficient

r=Σ[(x−x̄)(y−ȳ)]/√(Σ(x−x̄)²Σ(y−ȳ)²)

Common reference identity or relationship used in statistics & probability.

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