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Step 2: Then take a bootstrap sample (with replacement) <strong>of</strong> size equal to the original<br />

sample size and estimate the parameters using the EM algorithm.<br />

Step 3: Take at least 100 bootstrap samples and estimate the parameters.<br />

Step 4: Finally using these 100 bootstrap parameters calculates the standard errors <strong>of</strong> the<br />

estimates.<br />

5.6 Splus/R codes <strong>for</strong> the <strong>multivariate</strong> Poisson <strong>hidden</strong> Markov model<br />

We contributed to the <strong>hidden</strong> Markov model research area by developing Splus/R codes<br />

<strong>for</strong> the <strong>analysis</strong> <strong>of</strong> the <strong>multivariate</strong> Poisson <strong>hidden</strong> Markov model. Splus/R codes are<br />

written to estimate the <strong>multivariate</strong> Poisson <strong>hidden</strong> Markov model using the EM<br />

algorithm and the <strong>for</strong>ward-backward procedure and the estimation <strong>of</strong> bootstrapped<br />

standard errors. The estimated parameters were used to calculate the goodness <strong>of</strong> fit<br />

measures mention in this thesis: the entropy criterion (section 6.5) and the estimated<br />

unconditional variance-covariance matrix (section 7.3). Splus/R programs (see<br />

Appendix) <strong>of</strong> this thesis are available on request from the author.<br />

5.7 Loglinear <strong>analysis</strong><br />

Loglinear <strong>models</strong> were used to identify the covariance structure in this thesis. The<br />

loglinear model is a special case <strong>of</strong> generalized linear model (GLM) <strong>for</strong> count-type<br />

response variables modelled as Poisson data (Agresti, 2002). All generalized linear<br />

<strong>models</strong> have three components. The random component identifies the response variable<br />

102

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