\documentclass[addpoints,10pt]{exam} \usepackage{url} \usepackage{color} \usepackage{hyperref} \pagestyle{headandfoot} \runningheadrule \firstpageheadrule \firstpageheader{Scientific Computing}{Project Assignment}{11/05/2014 -- 11/06/2014} %\runningheader{Homework 01}{Page \thepage\ of \numpages}{23. October 2014} \firstpagefooter{}{}{} \runningfooter{}{}{} \pointsinmargin \bracketedpoints %\printanswers %\shadedsolutions \begin{document} %%%%%%%%%%%%%%%%%%%%% Submission instructions %%%%%%%%%%%%%%%%%%%%%%%%% \sffamily % \begin{flushright} % \gradetable[h][questions] % \end{flushright} \begin{center} \input{../disclaimer.tex} \end{center} %%%%%%%%%%%%%% Questions %%%%%%%%%%%%%%%%%%%%%%%%% \begin{questions} \question A subject was presented two possible objects for a very brief time ($50$ms). The task of the subject was to report which of the two objects was shown. In {\tt decisions.mat} you find an array that stores which object was presented in each trial and which object was reported by the subject. \begin{parts} \part Plot the data appropriately. \part Compute a 2-d histogram that shows how often different combinations of reported and presented came up. \part Normalize the histogram such that it sums to one (i.e. make it a probability distribution $P(x,y)$ where $x$ is the presented object and $y$ is the reported object). Compute the probability distributions $P(x)$ and $P(y)$ in the same way. \part Use that probability distribution to compute the mutual information $$I[x:y] = \sum_{x\in\{1,2\}}\sum_{y\in\{1,2\}} P(x,y) \log_2\frac{P(x,y)}{P(x)P(y)}$$ that the answers provide about the actually presented object. \part What is the maximally achievable mutual information (try to find out by generating your own dataset; the situation in which the information is maximal is pretty straightforward)? \part Use bootstrapping to compute the $95\%$ confidence interval for the mutual information estimate in that dataset. \end{parts} \end{questions} \end{document}