Abstract
<p><span id="page3R_mcid27" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*263.71px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.939886);" role="presentation">Markov processes (or Markov chains) are used for modeling a phenomenon in which changes over time of a random variable</span> <span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*272.95px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.91935);" role="presentation">comprise a sequence of values in the future, each of which depends only on the immediately preceding state, not on other past</span> <span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*282.19px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.915678);" role="presentation">states. A Markov process (PM) is completely characterized by specifying the finite set S of possible states and the stationary</span> <span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*291.31px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.934392);" role="presentation">probabilities (i.e. time-invariant) of transition between these states.</span></span><span id="page3R_mcid28" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*318.67px); top: calc(var(–scale-factor)*291.31px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.987133);" role="presentation">The</span></span><span id="page3R_mcid29" class="markedContent"></span><span id="page3R_mcid30" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*333.07px); top: calc(var(–scale-factor)*291.31px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.952517);" role="presentation">software</span></span><span id="page3R_mcid31" class="markedContent"></span><span id="page3R_mcid32" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*362.47px); top: calc(var(–scale-factor)*291.31px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.888688);" role="presentation">mos</span></span><span id="page3R_mcid33" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*375.82px); top: calc(var(–scale-factor)*291.31px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.879561);" role="presentation">t used</span></span><span id="page3R_mcid34" class="markedContent"></span><span id="page3R_mcid35" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*396.82px); top: calc(var(–scale-factor)*291.31px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.937188);" role="presentation">in medical applications</span></span><span id="page3R_mcid36" class="markedContent"></span><span id="page3R_mcid37" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*473.02px); top: calc(var(–scale-factor)*291.31px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.901263);" role="presentation">is</span></span><span id="page3R_mcid38" class="markedContent"></span><span id="page3R_mcid39" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*480.34px); top: calc(var(–scale-factor)*291.31px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.935546);" role="presentation">produced by </span></span><span id="page3R_mcid40" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*300.55px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.969267);" role="presentation">TreeAge</span></span><span id="page3R_mcid41" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*128.18px); top: calc(var(–scale-factor)*300.55px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif;" role="presentation">,</span></span><span id="page3R_mcid42" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*132.26px); top: calc(var(–scale-factor)*300.55px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.942177);" role="presentation">since it offers</span></span><span id="page3R_mcid43" class="markedContent"></span><span id="page3R_mcid44" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*177.89px); top: calc(var(–scale-factor)*300.55px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.933813);" role="presentation">many</span></span><span id="page3R_mcid45" class="markedContent"></span><span id="page3R_mcid46" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*197.69px); top: calc(var(–scale-factor)*300.55px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.932563);" role="presentation">advantages to the user. But, the cost of the Treeage software is relatively high.</span></span><span id="page3R_mcid47" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*454.42px); top: calc(var(–scale-factor)*300.55px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.964072);" role="presentation">Therefore in this</span></span><span id="page3R_mcid48" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*309.79px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.927866);" role="presentation">article two software alternatives are presented: Sto Tree</span></span><span id="page3R_mcid49" class="markedContent"></span><span id="page3R_mcid50" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*280.63px); top: calc(var(–scale-factor)*309.79px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.927152);" role="presentation">and</span></span><span id="page3R_mcid51" class="markedContent"></span><span id="page3R_mcid52" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*294.31px); top: calc(var(–scale-factor)*309.79px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.88554);" role="presentation">the zero cost ad</span></span><span id="page3R_mcid53" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*344.35px); top: calc(var(–scale-factor)*309.79px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif;" role="presentation">d</span></span><span id="page3R_mcid54" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*348.43px); top: calc(var(–scale-factor)*309.79px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif;" role="presentation">-</span></span><span id="page3R_mcid55" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*350.95px); top: calc(var(–scale-factor)*309.79px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.957184);" role="presentation">in package "markovchain" implemented in R. An</span></span><span id="page3R_mcid56" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*318.91px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.909639);" role="presentation">example of a cost</span></span><span id="page3R_mcid57" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*156.62px); top: calc(var(–scale-factor)*318.91px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif;" role="presentation">-</span></span><span id="page3R_mcid58" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*159.29px); top: calc(var(–scale-factor)*318.91px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.932854);" role="presentation">effectiveness analysis of two possible treatments for advanced cervical cancer, previously conducted with the</span></span><span id="page3R_mcid59" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*328.15px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.927157);" role="presentation">Treeage software, is re</span></span><span id="page3R_mcid60" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*173.21px); top: calc(var(–scale-factor)*328.15px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif;" role="presentation">-</span></span><span id="page3R_mcid61" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*175.85px); top: calc(var(–scale-factor)*328.15px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.916132);" role="presentation">analyzed with these two low cost software packages.</span></span> <span id="page3R_mcid63" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*337.27px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.95059);" role="presentation">You can find a Spanish version of this paper in the following link: http://faculty.sites.uci.edu/lrkeller/publications</span></span></p>