Exam 7: Random Variables and Discrete Probability Distributions

In the Poisson distribution,the mean is equal to the ____________________.

A(n)____________________ random variable is one whose values are uncountable.

The binomial probability distribution is a discrete probability distribution.

To find the probability that X is at most 10,you should find the probability that X is 10 or ____________________.

If the probability of success p remains constant in a binomial distribution,an increase in n will increase the variance.

In a Poisson distribution,the variance and standard deviation are equal.

The number of customers arriving at a department store in a 5-minute period has a Poisson distribution.

The number of days that a microcomputer goes without a breakdown is an example of a(n)____________________ random variable.

Which of the following is not a characteristic of a binomial experiment?

Evaluate the following binomial coefficients. a. b. c. d.

Mobile Phones Sales After analyzing sales data,the owner of a Mobile Phone store produced the following joint probability distribution of the number of iPhones (X)and Blackberries (Y)sold daily. ​ ​ -{Mobile Phones Sales Narrative} Compute the variance of the number of iPhones sold daily.

In a bivariate distribution,the sum of all the ____________________ probabilities must equal 1.

The number of accidents that occur at a busy intersection in one month is an example of a Poisson random variable.

A portfolio expected return E(R_p)of 3 stocks with the quantities w₁ = .40,w₂ = .50,w₃ = .10,E(R₁)= .10,E(R₂)= .15,and E(R₃)= .02 is equal to 0.117.

Golfing Store The joint probability distribution of variables X and Y is shown in the table below,where X is the number of drivers and Y is the number of putters sold daily in a small golfing store. ​ ​ -{Golfing Store Narrative} Calculate E(X + Y)and V(X + Y)directly by using the probability distribution of X + Y.

Suppose that the number of buses arriving at a Depot per minute is a Poisson process.If the average number of buses arriving per minute is 3,what is the probability that exactly 6 buses arrive in the next minute?

The covariance of two variables X and Y:

Which of the following is a discrete random variable?

If X and Y are independent variables,then their coefficient of correlation ρ = 0.

Shopping Outlet A shopping outlet estimates the probability distribution of the number of stores shoppers actually enter as shown in the table below. ​ ​ -{Shopping Outlet Narrative} What did you notice about the mean,variance,and standard deviation of Y = 2X + 1 in terms of the mean,variance,and standard deviation of X?