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Gaussian Distribution

PDF is given by $f(x) = \frac{1}{\sqrt{2\pi\sigma^2}}e^{-\frac{(x-\mu)^2}{2\sigma^2}}$ Where

  • $\mu$ is the mean
  • $\sigma$ is the standard deviation

Unit Normal distribution

  • $\mu = 0$
  • $\sigma = 1$

Characteristics

  • Continuous
  • Real values
  • Always positive
  • Doesn’t end in both direction

Uses

  • Many things in the real world resemble a gaussian
  • Not many things are exactly a gaussian because it extends forever and includes negative values
  • But we can approximate things to a gaussian
  • Another important use is the Central Limit Theorem
    • Any distribution no matter its type has a normally distributed sample mean
  • Gaussian is preserved under addition/subtraction
    • Suppose we have two random variables that are normally distributed. Then the sum of those two is also normally distributed