Reading 9: Common Probability Distributions习题

Reading 9: Common Probability Distributions

LOS a: Explain a probability distribution and distinguish between discrete and continuous random variables.

1、Which of the following statements about probability distributions is most accurate?

A)   A binomial distribution counts the number of successes that occur in a fixed number of independent trials that have mutually exclusive (i.e. yes or no) outcomes.

B)   A continuous uniform distribution has a lower limit but no upper limit.

C)   A cumulative distribution function defines the probability that a random variable is greater than a given value.

D)   A discrete uniform random variable has varying probabilities for each outcome that total to one.

The correct answer was A)     

Binomial probability distributions give the result of a single outcome and are used to study discrete random variables where you want to know the probability that an exact event will happen. A continuous uniform distribution has both an upper and a lower limit. A discrete uniform random variable has equal probabilities for each outcome. A cumulative distribution function defines the probability that a random variable is equal to or less than a given value.