If the parameter of an exponential distribution is 1,then which of the following is true?

A) The density function is e−x for x ≥ 0.
B) The mean is equal to 1.
C) The standard deviation and variance are both equal to 1.
D) All of these choices are true.

Exponential Distribution

The exponential distribution is a continuous probability distribution used to model the time or space between events in a Poisson process.

Density Function

A mathematical function that specifies the probability of a random variable taking on certain values.

Parameter

A quantity that influences the output or behavior of a mathematical function or statistical model, often fixed during the analysis.