Thanks Steve for explaining what the phi(x)dx and phi(y)dy terms represent. I have one clarification question on your response and two additional questions on other parts of this question (so thought easiest to keep in same thread).
1st Question: When you say 'given condition' (bold in quote above) are you referring to the the fact that both B1 and B2 take positive values or the fact that Y>-X or something else?
2nd Question: The solution to Part (i) of this question (9.4) says B2 has a zero probability of being exactly zero.
Is this because there is an almost infinite amount of possible values of B2 and therefore there is a zero probability that B2=any exact positive, negative or zero value. Or a different reason.
3rd Question: The solution to Part (iv) of this question (9.4) says "Bt will almost certainly take a negative value at some point close to t=0."
Why is Bt more likely to take a negative value close to t=0 rather than close to t=2?
Thanks in advance.
Last edited: Jul 31, 2022