代写Midterm Exam 1 - Economics 120a, Practice Exam代做Java程序

Midterm Exam 1 - Economics 120a, Practice Exam

Question 1. Does paying footballers more lead to more wins? Consider the relationship between total salaries (on the x axis) and wins (on the y axis) in the NFL in the 2006 season in the accompanying scatterplot.

(a) Is the correlation between salaries positive or negative?

(b) Does the relationship seem like it is strong or weak?

Question 2. Suppose a basketball team plays 3 games in a season and that the probability that it wins any given game is equal to 0.8. Also assume the outcome of each game is independent of each other.

(a) What is the probability the team wins a total of 1 game in a season? Show your work.

(b) Under the same assumptions, what is the probability the team has a winning season? That is, what is the probability that they win more than half their games? Show your work.

(c) What is the mean of the total number of wins?

Consider the following ’Dilbert’ comic strip.

(a) If the pointy haired boss (the one in the chair) really believed that two employees had only a 50% chance of finishing a project, what is the chance the project is completed if he assigns it to two workers (if the workers act independently)?

(b) Suppose that the boss gives the project to three workers (still with a 50% chance that each one completes the project). Now what is the chance it is completed?

Question 4: Suppose we have a random variable X which has the probability distribution given in the following table;

(a) What is the mean of this distribution?

(b) What is the variance of this distribution?

(c) Is the distribution symmetric?

Question 5. Suppose we have the distribution

(a) What is P(1 < x < 2)?

(b) What is the mean of X?