Recent content by alman9898

Wait, what? I don't think 5/(26*26) would be the right answer, since that implies there is a 5 in 26^2 chance that they get the answer right on the first try... My teacher has since told me to assume the attempts are independent (dumb hacker, I guess) so I'm modeling this as a geometric...

Homework Statement Consider a simple password scheme using only two lowercase letters. A hacker is given 5 chances to guess the pw before being detected. Computer probability hacker is successful. Homework Equations p = 1/(26*26) The Attempt at a Solution I'm assuming the...

Ok I understand it now. That clears up a lot, and explains the missing term I needed to make things all nice. (I would have another theta term in the numerator to cancel the one out in the denominator).

That helps a lot, but if it wasn't for checking my work I would've been surely wrong. Any idea why my method didn't work; it's a trick my professor uses to solve problems with 'known' solutions.

Homework Statement A density function used is: f(y) = \frac{2y}{\theta}e^{\frac{-y^{2}}{\theta}} y > 0 using method of transformations find: (a) pdf of U = Y^2 (b) E(Y) and V(Y) Homework Equations f(u) = f(h^-1(u))*|dh^-1/du| h^-1(u) = sqrt(u) The Attempt at a Solution The...

So, what exactly did I find when I have C(1,1)*C(4, i-1)/C(5,i) ... the conditional probability for Y = i ?

Homework Statement A box contains 5 keys, only one of which will open a lock. Keys are randomly selected and tried, one at a time, until the lock is opened (keys that do not work are discarded before another is tried). Let Y be the number of the trial on which the lock is opened. What is the...

Heres a try at the first one m = (a+n)/2 is an integer only if m is even which => (a+n) must be even. (a+n) is even if a & n are both even or both odd which covers a for both even and odd integers

Homework Statement Determine whether f: ZxZ->Z is onto if (a) f(m, n) = 2m-n (b) f(m, n) = n^2 - m^2 (c) f(m, n) = m + n + 1 (d) f(m, n) = |m| - |n| (e) f(m, n) = m^2 - 4Homework Equations A function is onto if for every y in the codomain there is at least one X in the domain st f(x) = y The...