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[bootstrap] improved code

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This commit is contained in:
Jan Benda 2020-12-07 22:37:36 +01:00
parent e1c6c32db0
commit 430bdfb7fd
4 changed files with 34 additions and 33 deletions
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5
bootstrap/code/bootstrapsem.m
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@ -1,7 +1,7 @@
nsamples = 100; nsamples = 100;
nresamples = 1000; nresamples = 1000;
% draw a SRS (simple random sample, "Stichprobe") from the population: % draw a simple random sample ("Stichprobe") from the population:
x = randn(1, nsamples); x = randn(1, nsamples);
fprintf('%-30s %-5s %-5s %-5s\n', '', 'mean', 'stdev', 'sem') fprintf('%-30s %-5s %-5s %-5s\n', '', 'mean', 'stdev', 'sem')
fprintf('%30s %5.2f %5.2f %5.2f\n', 'single SRS', mean(x), std(x), std(x)/sqrt(nsamples)) fprintf('%30s %5.2f %5.2f %5.2f\n', 'single SRS', mean(x), std(x), std(x)/sqrt(nsamples))
@ -15,7 +15,8 @@ for i = 1:nresamples % loop for generating the bootstraps
end end
fprintf('%30s %5.2f %5.2f -\n', 'bootstrapped distribution', mean(mus), std(mus)) fprintf('%30s %5.2f %5.2f -\n', 'bootstrapped distribution', mean(mus), std(mus))
% many SRS (we can do that with the random number generator, but not in real life!): % many SRS (we can do that with the random number generator,
% but not in real life!):
musrs = zeros(nresamples,1); % vector for the means of each SRS musrs = zeros(nresamples,1); % vector for the means of each SRS
for i = 1:nresamples for i = 1:nresamples
x = randn(1, nsamples); % draw a new SRS x = randn(1, nsamples); % draw a new SRS