| Sample 1. Prove that:
Mean Squared Error = (Standard Error)2
+ Bias2
(Hint: use the fact that var(X) = E(X2)
– E(X)2.)
Sample 2. Consider a modification of sample variance
as an estimator for the variance of a random variable X.
Suppose we happen to know the mean
of X. Replacing the sample mean with
that known mean
in the formula for S2, we obtain a new
estimator for variance:

What is the bias of this estimator?
Sample 3: Consider the data:

Use general regression to fit a curve of the form:

to the data.
Sample 4: Solve for y as a function of x:

Sample 5: Consider the exponential Brownian motion:
X = exp( W
+ t)
Apply Ito's lemma to calculate dX.
Sample 6: If

find the stochastic differential equations satisfied by
a. f(X) = AX
b. f(X) = AXn. |