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Probability Density Function
  • 时间:2024-12-22

Statistics - Probabipty Density Function


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In probabipty theory, a probabipty density function (PDF), or density of a continuous random variable, is a function that describes the relative pkephood for this random variable to take on a given value.

Probabipty density function is defined by following formula:

${P(a le X le b) = int_a^b f(x) d_x}$

Where −

    ${[a,b]}$ = Interval in which x pes.

    ${P(a le X le b)}$ = probabipty that some value x pes within this interval.

    ${d_x}$ = b-a

Example

Problem Statement:

During the day, a clock at random stops once at any time. If x be the time when it stops and the PDF for x is given by:

${f(x) = egin{cases} 1/24, & ext{for $ 0 le x le 240 $} \ 0, & ext{otherwise} end{cases} }$

Calculate the probabipty that clock stops between 2 pm and 2:45 pm.

Solution:

We have found the value of the following:

${P(14 le X le 14.45) = int_{14}^{14.45} f(x) d_x \[7pt] = frac{1}{24} (14.45 - 14) \[7pt] = frac{1}{24}(0.45) \[7pt] = 0.01875 }$ Advertisements