From e894f937aabb648ef88bca530c1709da11e1947c Mon Sep 17 00:00:00 2001 From: Mark Date: Wed, 4 Sep 2024 22:50:57 -0700 Subject: [PATCH] More secratary edits --- .../Stopping Problems/parts/1 secretary.tex | 48 ++++++++++++++++++- 1 file changed, 46 insertions(+), 2 deletions(-) diff --git a/Advanced/Stopping Problems/parts/1 secretary.tex b/Advanced/Stopping Problems/parts/1 secretary.tex index e10cdbc..09807f8 100644 --- a/Advanced/Stopping Problems/parts/1 secretary.tex +++ b/Advanced/Stopping Problems/parts/1 secretary.tex @@ -79,7 +79,7 @@ We have no absolute metric by which to judge each candidate. \vspace{2mm} -Thus, all $I_x$ defined above are independent: \par +Thus, all $I_x$ defined above are independent: the outcome of any $I_a$ does not influence the probabilities of any other $I_b$. \vspace{2mm} @@ -92,4 +92,48 @@ the results of past $I_x$ cannot possibly provide information about future $I_x$ Given the above realizations, we are left with only one kind of strategy: \par We blindly reject the first $k$ applicants, and select the first \say{best-seen} applicant we encounter afterwards. -All we need to do now is pick the optimal $k$. \ No newline at end of file +All we need to do now is pick the optimal $k$. + +\pagebreak + +\problem{} +Consider the secretary problem with a given $n$. \par +What is the probability distribution of each of $I_1, I_2, ..., I_n$? \par +\note{That is, what are $\mathcal{P}(I_x = \texttt{0})$ and $\mathcal{P}(I_x = \texttt{1})$ for each $x$?} + +\vfill + +\problem{} +What is the probability that the $x^\text{th}$ applicant is \textit{not} the best-seen applicant? \par +In other words, what is the probability we reject the $x^\text{th}$ candidate? \par +\note{Assuming that $x > k$. Otherwise, the probability of rejection is 1!} + +\vfill + +\problem{} +Again, consider the secretary problem with a fixed $n$. \par +If we reject the first $k$ applicants and hire the first \say{best-yet} applicant we encounter, \par +what is the probability that we select the best candidate? \par +Call this function $\phi_n(k)$. + +\vfill + +\problem{} +Find $ + \underset{x \in \{0, ..., n\}}{\text{max}} + \Bigl(\phi_n(k)\Bigr) +$ for all $n$ in $\{1, 2, 3, 4, 5\}$. + +\vfill + +\problem{} +Find $ + \underset{x \in \mathbb{R}}{\text{max}} + \Bigl(~ + \underset{n \rightarrow \infty}{\text{lim}} + \phi_n(k) + ~\Bigr) +$ + + +\vfill \ No newline at end of file