- #1
acgold
- 16
- 0
Suppose that X and Y are independent random variables, where X is normally distributed with mean 45 and standard deviation 0.5 and Y is normally distributed with mean 20 and standard deviation 0.1.
(a) [tex] Find \ P(40 \leq X \leq 50, \ 20 \leq Y \leq 25). [/tex] Ans. ~0.5
(b) [tex] Find \ P(4(X-45)^2+100(Y-20)^2 \leq 2). [/tex] Ans. ~0.632
Part (a) is easy. I used Maple to find the double integral of the joint density function from [tex] 40 \leq X \leq 50, \ 20 \leq Y \leq 25. [/tex] and I get 0.5
Part (b) is my problem. How do I find the limits of integration? I tried solving for X and Y but I couldn't get that to work. Am I missing something easy here? Please please please help me! This assignment is due tomorrow and I've been stuck on this problem for days.
(a) [tex] Find \ P(40 \leq X \leq 50, \ 20 \leq Y \leq 25). [/tex] Ans. ~0.5
(b) [tex] Find \ P(4(X-45)^2+100(Y-20)^2 \leq 2). [/tex] Ans. ~0.632
Part (a) is easy. I used Maple to find the double integral of the joint density function from [tex] 40 \leq X \leq 50, \ 20 \leq Y \leq 25. [/tex] and I get 0.5
Part (b) is my problem. How do I find the limits of integration? I tried solving for X and Y but I couldn't get that to work. Am I missing something easy here? Please please please help me! This assignment is due tomorrow and I've been stuck on this problem for days.