{"id":77,"date":"2014-12-26T13:06:11","date_gmt":"2014-12-26T13:06:11","guid":{"rendered":"http:\/\/frees.pajarel.net\/?page_id=77"},"modified":"2015-02-20T16:04:28","modified_gmt":"2015-02-20T22:04:28","slug":"lifetime-moments","status":"publish","type":"page","link":"https:\/\/users.ssc.wisc.edu\/~ewfrees\/actuarial-mathematics\/classic-joint-life-models\/1-joint-life-fundamentals\/lifetime-moments\/","title":{"rendered":"Lifetime Moments"},"content":{"rendered":"<p>For the expected survivor time of the joint life status, we have<br \/>\n\\begin{eqnarray*}<br \/>\n\\dot{e}_{xy} = E ~ T(xy) &#038;=&#038; \\int_0^{\\infty} t f_T(xy)(t) dt =<br \/>\n\\int_0^{\\infty} (1-<br \/>\nF_T(xy)(t)) dt \\\\<br \/>\n&#038;=&#038; \\int_0^{\\infty} ~_t p_{xy} dt .<br \/>\n\\end{eqnarray*} The third equality comes from an integration by parts.<\/p>\n<p>Similarly, for the expected last-survivor time,<br \/>\n\\begin{eqnarray*}<br \/>\n\\dot{e}_{\\overline{xy}} &#038;=&#038; E ~ T(\\overline{xy}) = \\int_0^{\\infty}<br \/>\n~_t p_{\\overline{xy}} ~ dt \\\\<br \/>\n&#038;=&#038; \\int_0^{\\infty}<br \/>\n\\left(~_t p_x + ~_t p_y &#8211; ~_t p_{xy}\\right) dt \\\\<br \/>\n&#038;=&#038; \\dot{e}_{x}+\\dot{e}_{y}-\\dot{e}_{xy}.<br \/>\n\\end{eqnarray*} Note that this relation holds without regard to the independence between lives assumption.<br \/>\n<div class=\"alignleft\"><a href=\"https:\/\/users.ssc.wisc.edu\/~ewfrees\/actuarial-mathematics\/classic-joint-life-models\/1-joint-life-fundamentals\/life-expectancy-exercise\/\" title=\"Life Expectancy Exercise\">&#9668 Previous page<\/a><\/div><div class=\"alignright\"><a href=\"https:\/\/users.ssc.wisc.edu\/~ewfrees\/actuarial-mathematics\/classic-joint-life-models\/1-joint-life-fundamentals\/lifetime-moments\/special-case-exponential-distribution\/\" title=\"Special Case &#8211; Exponential Distribution\">Next page &#9658<\/a><\/div><\/p>\n","protected":false},"excerpt":{"rendered":"<p>For the expected survivor time of the joint life status, we have \\begin{eqnarray*} \\dot{e}_{xy} = E ~ T(xy) &#038;=&#038; \\int_0^{\\infty} t f_T(xy)(t) dt = \\int_0^{\\infty} (1- F_T(xy)(t)) dt \\\\ &#038;=&#038; \\int_0^{\\infty} ~_t p_{xy} dt . &hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":43,"menu_order":6,"comment_status":"closed","ping_status":"closed","template":"","meta":{"jetpack_post_was_ever_published":false},"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/P8cLPd-1f","acf":[],"_links":{"self":[{"href":"https:\/\/users.ssc.wisc.edu\/~ewfrees\/wp-json\/wp\/v2\/pages\/77"}],"collection":[{"href":"https:\/\/users.ssc.wisc.edu\/~ewfrees\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/users.ssc.wisc.edu\/~ewfrees\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/users.ssc.wisc.edu\/~ewfrees\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/users.ssc.wisc.edu\/~ewfrees\/wp-json\/wp\/v2\/comments?post=77"}],"version-history":[{"count":3,"href":"https:\/\/users.ssc.wisc.edu\/~ewfrees\/wp-json\/wp\/v2\/pages\/77\/revisions"}],"predecessor-version":[{"id":1016,"href":"https:\/\/users.ssc.wisc.edu\/~ewfrees\/wp-json\/wp\/v2\/pages\/77\/revisions\/1016"}],"up":[{"embeddable":true,"href":"https:\/\/users.ssc.wisc.edu\/~ewfrees\/wp-json\/wp\/v2\/pages\/43"}],"wp:attachment":[{"href":"https:\/\/users.ssc.wisc.edu\/~ewfrees\/wp-json\/wp\/v2\/media?parent=77"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}