two random variables X, Y (not necessarily independent), and two real numbers a and b. Prove that Var(aX+bY) = a² Var(X)+b² Var(Y)+2ab Cov(X,Y). (Hint: Use the properties of Cov() reviewed in class.) Prove that E[{X – E(X)}²] = E(X²) – {E(X)}², i.e., the two expressions | for Var(X) are indeed equivalent. Prove that E[{X – E(X | Y)}² | Y] = E(X² | Y) – {E(X | Y)}², i.e., the two expressions for Var(X | Y) are indeed equivalent.

Advanced Engineering Mathematics
10th Edition
ISBN:9780470458365
Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
Section: Chapter Questions
Problem 1RQ
icon
Related questions
Question

show work, need it to study

two random variables X, Y (not necessarily independent), and two
real numbers a and b. Prove that Var(aX+bY) = a² Var(X)+b² Var(Y)+2ab Cov(X,Y).
(Hint: Use the properties of Cov() reviewed in class.)
Prove that E[{X – E(X)}²] = E(X²) – {E(X)}², i.e., the two expressions
for Var(X) are indeed equivalent.
Prove that E[{X – E(X | Y)}² | Y] = E(X² | Y) – {E(X | Y)}², i.e., the
two expressions for Var(X | Y) are indeed equivalent.
Transcribed Image Text:two random variables X, Y (not necessarily independent), and two real numbers a and b. Prove that Var(aX+bY) = a² Var(X)+b² Var(Y)+2ab Cov(X,Y). (Hint: Use the properties of Cov() reviewed in class.) Prove that E[{X – E(X)}²] = E(X²) – {E(X)}², i.e., the two expressions for Var(X) are indeed equivalent. Prove that E[{X – E(X | Y)}² | Y] = E(X² | Y) – {E(X | Y)}², i.e., the two expressions for Var(X | Y) are indeed equivalent.
Expert Solution
steps

Step by step

Solved in 3 steps

Blurred answer
Recommended textbooks for you
Advanced Engineering Mathematics
Advanced Engineering Mathematics
Advanced Math
ISBN:
9780470458365
Author:
Erwin Kreyszig
Publisher:
Wiley, John & Sons, Incorporated
Numerical Methods for Engineers
Numerical Methods for Engineers
Advanced Math
ISBN:
9780073397924
Author:
Steven C. Chapra Dr., Raymond P. Canale
Publisher:
McGraw-Hill Education
Introductory Mathematics for Engineering Applicat…
Introductory Mathematics for Engineering Applicat…
Advanced Math
ISBN:
9781118141809
Author:
Nathan Klingbeil
Publisher:
WILEY
Mathematics For Machine Technology
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,
Basic Technical Mathematics
Basic Technical Mathematics
Advanced Math
ISBN:
9780134437705
Author:
Washington
Publisher:
PEARSON
Topology
Topology
Advanced Math
ISBN:
9780134689517
Author:
Munkres, James R.
Publisher:
Pearson,