Two different computer systems are monitored foratotalofnweeks. letxidenote the number ofbreakdowns of the first system during theith week, and suppose thexi’s are independent and drawnfrom a poisson distribution with parameterl1. sim-ilarly, letyidenote the number of breakdowns week, and assumeindependence with eachyipoisson with parameterl2. derive the mle’s ofl1,l2,andl1–l2.[hint: using independence, write the joint pmf (likeli-hood)ofthexi’s andyi’s together.]