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@stdlib/stats

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Standard library statistical functions.

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{{alias}}( x, λ ) Evaluates the probability density function (PDF) for an exponential distribution with rate parameter `λ` at a value `x`. If provided `NaN` as any argument, the function returns `NaN`. If provided a negative value for `λ`, the function returns `NaN`. Parameters ---------- x: number Input value. λ: number Rate parameter. Returns ------- out: number Evaluated PDF. Examples -------- > var y = {{alias}}( 0.3, 4.0 ) ~1.205 > y = {{alias}}( 2.0, 0.7 ) ~0.173 > y = {{alias}}( -1.0, 0.5 ) 0.0 > y = {{alias}}( 0, NaN ) NaN > y = {{alias}}( NaN, 2.0 ) NaN // Negative rate: > y = {{alias}}( 2.0, -1.0 ) NaN {{alias}}.factory( λ ) Returns a function for evaluating the probability density function (PDF) for an exponential distribution with rate parameter `λ`. Parameters ---------- λ: number Rate parameter. Returns ------- pdf: Function Probability density function (PDF). Examples -------- > var myPDF = {{alias}}.factory( 0.5 ); > var y = myPDF( 3.0 ) ~0.112 See Also --------