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Student's t-Distribution Calculator

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Student's t-Distribution: Definition, Properties, and Applications

Student's t-Distribution

Definition: The Student's t-distribution is a continuous probability distribution that arises when estimating the mean of a normally distributed population in situations where the sample size is small and the population standard deviation is unknown.

Formula:The probability density function (PDF) is given by:f(t)=Γ((ν+1)/2)νπΓ(ν/2)(1+t2ν)(ν+1)/2f(t) = \frac{\Gamma((\nu+1)/2)}{\sqrt{\nu\pi}\Gamma(\nu/2)}\left(1+\frac{t^2}{\nu}\right)^{-(\nu+1)/2}Where:ν=degrees of freedom\nu = \text{degrees of freedom}Γ=gamma function\Gamma = \text{gamma function}

Properties

  • Mean: E(X)=0E(X) = 0 for ν>1\nu > 1
  • Variance: Var(X)=νν2\text{Var}(X) = \frac{\nu}{\nu-2} for ν>2\nu > 2
  • Key Characteristics:
    • Bell-shaped and symmetric about 0
    • More peaked and heavier tails than normal distribution
    • Approaches normal distribution as ν increases
    • Support is all real numbers

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