Prof. Bryan Caplan

http://www.gmu.edu/departments/economics/bcaplan

Spring, 1998

Econometrics Pre-Test

This class requires competence in linear algebra and intermediate mathematical statistics. You should definitely take the following pre-test to see how much effort you should allocate to review. Answers for self-evaluation will be available next class.

Feel free to use books and calculators when taking the test, but spend no more than 90 minutes working on it.

If you find this exam difficult, it means that you should immediately begin intensive review of the areas where you feel shaky.

Find E(X), E(X^{2}), Var(X), and SD(X), where X is:

1. A random variable that is equal to 0 25% of the time, 1 50% of the time, 2 20% of the time, and 10 5% of the time.

Evaluate the following expressions:

1.

2.

Determine the Probability of the Following Events:

*X* is a normal six-sided die; *Y* is a die with four sides numbered {1,2,3,4}.

1. P(*X*<5|*X+Y*=8)

2. P(*X+Y>*4|*X<5*)

Evaluate the Following Expressions:

;

- XY
- X'-Y
- rank(XY-)
- (XY)
^{-1}

5. ; . Solve the following equation for *B*: .