HW1soln - Problem 1(a Mean function ret=mymean(a...

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Unformatted text preview: Problem 1: (a) Mean: function ret=mymean(a) ret=sum(a)/length(a); endfunction Mode: function ret=mymode (a) z=zeros(1, length(a)); for ii=1:length(a) for jj=1:length(a) if ((a(jj)-a(ii))==0) z(ii)=z(ii)+1; end end end [w,iw]=max(z); ret=a(iw); endfunction Median: function ret=mymedian(a) asort=sort(a); N=length(a); if ceil(N/2)==floor(N/2) ret=(asort(N/2)+asort(N/2+1))/2; else ret=asort(ceil(N/2)); end endfunction Variance: function ret=myvariance(a) ret= sum((a-mymean(a)).^2)/(length(a)-1); endfunction Standard Deviation: function ret=mystdev(a) ret=sqrt(myvariance(a)); endfunction a=[0.91595 0.35290 0.35692 0.18598 0.67537 0.92017 0.98268 0.44933 0.27089 0.81826]; mymean(a) ans = 0.59284 mymode(a) ans = 0.91595 mymedian(a) ans = 0.56235 mystdev(a) ans = 0.30261 myvariance(a) ans = 0.091573 a1000=rand(1000,1); mymean(a1000) ans = 0.50032 mymode(a1000) ans = 0.19736 mymedian(a1000) ans = 0.50370 mystdev(a1000) ans = 0.28774 myvariance(a1000) ans = 0.082792 (b) Generate random numbers from Gaussian PDF: function ret=mygaussian(xmean, xsigma) ret=; while (isempty(ret)) x=xmean+(0.5-rand)*8*xsigma; %4 sigma range if rand<(e^(-((x-xmean)^2)/(2*xsigma^2))) ret=x; end end endfunction Show that this works: for ii=1:1000 g(ii)=mygaussian(100,10); end hist(g) Demonstrate that the standard deviation of the mean tends to zero as the sample size increases: clear; xmean=100; xsigma=10; Ns=5:5:100; kk=1; for N=Ns jj=1; for samples=1:25 %num. of samples to calculate stdev from for ii=1:N a(ii)=mygaussian(xmean,xsigma);...
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This note was uploaded on 12/29/2011 for the course PHYSICS 375 taught by Professor Eno during the Spring '11 term at Maryland.

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HW1soln - Problem 1(a Mean function ret=mymean(a...

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