Talk:Probability density function
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It would be nice to have a picture of a PDF, of, say, the normal distribution. -iwakura
Hi all:
Can someone help me in computing
Indefinite Integral (f(x)^((1/r)+1)) dx where r>=1
in terms of Indefinite Integral (f(x)) dx
Here, f(x) is an arbitrary probability density function.
Partho
what is a multimodal pdf ? the article should touch this topic. - rodrigob.
Simple English
In simple english. The probability density function is any function f(x) that describe the probability density in terms of the input variable x. With two further conditions that
- f(x) is greater than or equal to zero for all values of x
- The total area under the graph is 1. Refer to equation below.
- <math> \int_{-\infty}^\infty \,f(x)\,dx = 1 <math>
The actual probability can then be calculated by taking the integral of the function f(x) by the integration interval of the input variable x .
For example: the variable x being within the interval 4.3 < x < 7.8 would have the actual probability of
- <math>p(4.3
what is a probability density?
Given that it is a common mistake to interpret the y-axis of the probability density function as representing probability (as is often done with the normal curve), it would be helpful to have a common-sense description of what probability *density* is. It's clearly related to actual probability, but does it have a "real-world" correlate? How should "density" be interpreted? --anon
Answer: If "probability" is equivalent to "distance travelled" then "probability density" is equivalent to "speed". So the "probability density function of input variable x " is equivalent to "speed function of input variable t" where t stands for time. -ohanian
- One more answer: If you have a random variable, then it can take many values. But, most of the time those values are not equally likely, some of them occur more often than others. So, if a value of this variable is more likely, the density of that variable is higher at that value. If certain value does not occur at all, the density at that value is zero. This explanation is not at all rigurious, but it might drive the point home. Oleg Alexandrov 15:03, 2 Jun 2005 (UTC)