Final answer:
The probability density function (pdf) is used to describe probabilities for continuous random variables. It represents the area under the density curve between two points, which corresponds to the probability that the variable falls between those two values.
Step-by-step explanation:
The probability density function (pdf) is used to describe probabilities for continuous random variables. It is denoted as f(x). The area under the density curve between two points corresponds to the probability that the variable falls between those two values. For example, if we have a continuous random variable X and we want to find the probability of it falling between 2 and 10, we would calculate P(2<x<10), which is the area under the density curve between these two values.