Chi-Squared Distribution with Threshold

Probability Density Function (PDF)

Cumulative Distribution Function (CDF)

where 𝛤(𝑘) is the Gamma function, and 𝛾(𝑘, 𝑧) is the lower incomplete Gamma function.

Range 0 ≤ 𝑥 - 𝜃 < ∞

Shape parameter 𝜈 > 0, the degrees of freedom

Threshold parameter 𝜃 < 𝑚𝑖𝑛(𝑥)