Which of the following is true about probability density functions?
A) A graph of the density function must lie at or below the x-axis.
B) The total area under the density function below the x-axis is 2.0.
C) It calculates the probability of a random variable lying within a certain interval.
D) P (a) x P (b) is the area under the density function between two numbers a and b.

Question

Quizplus · Accepted Answer

Probability density functions calculate the probability of a random variable lying within a certain interval. A is false because the graph must have an area of 1 under it, not at or below the x-axis. B is false because the area under the density function must be equal to 1, not 2. D is false because the area under the density function between two numbers a and b is the probability that the random variable falls between a and b, not the product of the probabilities of a and b.

Which of the Following Is True About Probability Density Functions