{"id":2304,"date":"2022-04-16T19:16:03","date_gmt":"2022-04-16T19:16:03","guid":{"rendered":"https:\/\/mdr.foobrdigital.com\/?p=2304"},"modified":"2022-04-16T19:16:03","modified_gmt":"2022-04-16T19:16:03","slug":"probabilistic-reasoning-in-ai","status":"publish","type":"post","link":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/2022\/04\/16\/probabilistic-reasoning-in-ai\/","title":{"rendered":"Probabilistic reasoning in AI"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">Uncertainty:<\/h2>\n\n\n\n<p>Till now, we have learned knowledge representation using first-order logic and propositional logic with certainty, which means we were sure about the predicates. With this knowledge representation, we might write A\u2192B, which means if A is true then B is true, but consider a situation where we are not sure about whether A is true or not then we cannot express this statement, this situation is called uncertainty.<\/p>\n\n\n\n<p>So to represent uncertain knowledge, where we are not sure about the predicates, we need uncertain reasoning or probabilistic reasoning.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Causes of uncertainty:<\/h2>\n\n\n\n<p>Following are some leading causes of uncertainty to occur in the real world.<\/p>\n\n\n\n<ol><li>Information occurred from unreliable sources.<\/li><li>Experimental Errors<\/li><li>Equipment fault<\/li><li>Temperature variation<\/li><li>Climate change.<\/li><\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">Probabilistic reasoning:<\/h2>\n\n\n\n<p>Probabilistic reasoning is a way of knowledge representation where we apply the concept of probability to indicate the uncertainty in knowledge. In probabilistic reasoning, we combine probability theory with logic to handle the uncertainty.<\/p>\n\n\n\n<p>We use probability in probabilistic reasoning because it provides a way to handle the uncertainty that is the result of someone&#8217;s laziness and ignorance.<\/p>\n\n\n\n<p>In the real world, there are lots of scenarios, where the certainty of something is not confirmed, such as &#8220;It will rain today,&#8221; &#8220;behavior of someone for some situations,&#8221; &#8220;A match between two teams or two players.&#8221; These are probable sentences for which we can assume that it will happen but not sure about it, so here we use probabilistic reasoning.<\/p>\n\n\n\n<p><strong>Need of probabilistic reasoning in AI:<\/strong><\/p>\n\n\n\n<ul><li>When there are unpredictable outcomes.<\/li><li>When specifications or possibilities of predicates becomes too large to handle.<\/li><li>When an unknown error occurs during an experiment.<\/li><\/ul>\n\n\n\n<p>In probabilistic reasoning, there are two ways to solve problems with uncertain knowledge:<\/p>\n\n\n\n<ul><li><strong>Bayes&#8217; rule<\/strong><\/li><li><strong>Bayesian Statistics<\/strong><\/li><\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">Note: We will learn the above two rules in later chapters.<\/h4>\n\n\n\n<p>As probabilistic reasoning uses probability and related terms, so before understanding probabilistic reasoning, let&#8217;s understand some common terms:<\/p>\n\n\n\n<p><strong>Probability:<\/strong>&nbsp;Probability can be defined as a chance that an uncertain event will occur. It is the numerical measure of the likelihood that an event will occur. The value of probability always remains between 0 and 1 that represent ideal uncertainties.<a href=\"https:\/\/www.javatpoint.com\/probabilistic-reasoning-in-artifical-intelligence#\"><\/a><a href=\"https:\/\/www.javatpoint.com\/probabilistic-reasoning-in-artifical-intelligence#\"><\/a><a href=\"https:\/\/www.javatpoint.com\/probabilistic-reasoning-in-artifical-intelligence#\"><\/a><\/p>\n\n\n\n<ol><li>0&nbsp;\u2264&nbsp;P(A)&nbsp;\u2264&nbsp;1,&nbsp;&nbsp;&nbsp;where&nbsp;P(A)&nbsp;is&nbsp;the&nbsp;probability&nbsp;of&nbsp;an&nbsp;event&nbsp;A.&nbsp;&nbsp;<\/li><\/ol>\n\n\n\n<p><a href=\"https:\/\/www.javatpoint.com\/probabilistic-reasoning-in-artifical-intelligence#\"><\/a><a href=\"https:\/\/www.javatpoint.com\/probabilistic-reasoning-in-artifical-intelligence#\"><\/a><a href=\"https:\/\/www.javatpoint.com\/probabilistic-reasoning-in-artifical-intelligence#\"><\/a><\/p>\n\n\n\n<ol><li>P(A)&nbsp;=&nbsp;0,&nbsp;&nbsp;indicates&nbsp;total&nbsp;uncertainty&nbsp;in&nbsp;an&nbsp;event&nbsp;A.&nbsp;&nbsp;&nbsp;<\/li><\/ol>\n\n\n\n<p><a href=\"https:\/\/www.javatpoint.com\/probabilistic-reasoning-in-artifical-intelligence#\"><\/a><a href=\"https:\/\/www.javatpoint.com\/probabilistic-reasoning-in-artifical-intelligence#\"><\/a><a href=\"https:\/\/www.javatpoint.com\/probabilistic-reasoning-in-artifical-intelligence#\"><\/a><\/p>\n\n\n\n<ol><li>P(A)&nbsp;=1,&nbsp;indicates&nbsp;total&nbsp;certainty&nbsp;in&nbsp;an&nbsp;event&nbsp;A.&nbsp;&nbsp;&nbsp;&nbsp;<\/li><\/ol>\n\n\n\n<p>We can find the probability of an uncertain event by using the below formula.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/static.javatpoint.com\/tutorial\/ai\/images\/probabilistic.png\" alt=\"Probabilistic reasoning in Artificial intelligence\"\/><\/figure>\n\n\n\n<ul><li>P(\u00acA) = probability of a not happening event.<\/li><li>P(\u00acA) + P(A) = 1.<\/li><\/ul>\n\n\n\n<p><strong>Event:<\/strong>&nbsp;Each possible outcome of a variable is called an event.<\/p>\n\n\n\n<p><strong>Sample space:<\/strong>&nbsp;The collection of all possible events is called sample space.<\/p>\n\n\n\n<p><strong>Random variables:<\/strong>&nbsp;Random variables are used to represent the events and objects in the real world.<\/p>\n\n\n\n<p><strong>Prior probability:<\/strong>&nbsp;The prior probability of an event is probability computed before observing new information.<\/p>\n\n\n\n<p><strong>Posterior Probability:<\/strong>&nbsp;The probability that is calculated after all evidence or information has taken into account. It is a combination of prior probability and new information.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Conditional probability:<\/h2>\n\n\n\n<p>Conditional probability is a probability of occurring an event when another event has already happened.<\/p>\n\n\n\n<p>Let&#8217;s suppose, we want to calculate the event A when event B has already occurred, &#8220;the probability of A under the conditions of B&#8221;, it can be written as:<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/static.javatpoint.com\/tutorial\/ai\/images\/probabilistic2.png\" alt=\"Probabilistic reasoning in Artificial intelligence\"\/><\/figure>\n\n\n\n<p><strong>Where P(<em>A<\/em>\u22c0<em>B<\/em>)= Joint probability of a and B<\/strong><\/p>\n\n\n\n<p><strong>P(B)= Marginal probability of B.<\/strong><\/p>\n\n\n\n<p>If the probability of A is given and we need to find the probability of B, then it will be given as:<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/static.javatpoint.com\/tutorial\/ai\/images\/probabilistic3.png\" alt=\"Probabilistic reasoning in Artificial intelligence\"\/><\/figure>\n\n\n\n<p>It can be explained by using the below Venn diagram, where B is occurred event, so sample space will be reduced to set B, and now we can only calculate event A when event B is already occurred by dividing the probability of&nbsp;<strong>P(A\u22c0<em>B<\/em>) by P( B )<\/strong>.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/static.javatpoint.com\/tutorial\/ai\/images\/probabilistic4.png\" alt=\"Probabilistic reasoning in Artificial intelligence\"\/><\/figure>\n\n\n\n<p><strong>Example:<\/strong><\/p>\n\n\n\n<p>In a class, there are 70% of the students who like English and 40% of the students who likes English and mathematics, and then what is the percent of students those who like English also like mathematics?<\/p>\n\n\n\n<p><strong>Solution:<\/strong><\/p>\n\n\n\n<p>Let, A is an event that a student likes Mathematics<\/p>\n\n\n\n<p>B is an event that a student likes English.<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"https:\/\/static.javatpoint.com\/tutorial\/ai\/images\/probabilistic5.png\" alt=\"Probabilistic reasoning in Artificial intelligence\"\/><\/figure>\n\n\n\n<p><strong>Hence, 57% are the students who like English also like Mathematics.<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Uncertainty: Till now, we have learned knowledge representation using first-order logic and propositional logic with certainty, which means we were sure about the predicates. With this knowledge representation, we might write A\u2192B, which means if A is true then B is true, but consider a situation where we are not sure about whether A is [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[906],"tags":[],"_links":{"self":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/posts\/2304"}],"collection":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/comments?post=2304"}],"version-history":[{"count":0,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/posts\/2304\/revisions"}],"wp:attachment":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/media?parent=2304"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/categories?post=2304"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/tags?post=2304"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}