Is it possible for an event A to be independent from event B, but not the other way around? Announcing the arrival of Valued Associate #679: Cesar Manara Planned maintenance scheduled April 23, 2019 at 23:30 UTC (7:30pm US/Eastern)Zero probability and impossibilityExchangeable Random Variable but not independent?Probability of being away from mean for independent random variablesAn example of two random variables that are mean independent but not independentCalculating probability when order matters only sometimesIf X is independent to Y and Z, does it imply that X is independent to YZ ?Representing pairwise-independent but not independent occurrences with venn diagramPairwise independent events but not mutually independentExamples of situation in which two events are independent but one event can be predicted perfectly once we know if the other happened or not.Suppose $A $ and $B$ are independent events. For an event $C $ such that $P(C) > 0$ , prove that the event of $A$ given $C $

What are the main differences between the original Stargate SG-1 and the Final Cut edition?

How to change the tick of the color bar legend to black

Mounting TV on a weird wall that has some material between the drywall and stud

What is the origin of 落第?

Moving a wrapfig vertically to encroach partially on a subsection title

How can I save and copy a screenhot at the same time?

What is the difference between a "ranged attack" and a "ranged weapon attack"?

Is openssl rand command cryptographically secure?

What would you call this weird metallic apparatus that allows you to lift people?

Getting out of while loop on console

In musical terms, what properties are varied by the human voice to produce different words / syllables?

Universal covering space of the real projective line?

AppleTVs create a chatty alternate WiFi network

What is the "studentd" process?

Central Vacuuming: Is it worth it, and how does it compare to normal vacuuming?

What does 丫 mean? 丫是什么意思?

How does light 'choose' between wave and particle behaviour?

Why weren't discrete x86 CPUs ever used in game hardware?

As a dual citizen, my US passport will expire one day after traveling to the US. Will this work?

Tips to organize LaTeX presentations for a semester

After Sam didn't return home in the end, were he and Al still friends?

Did any compiler fully use 80-bit floating point?

Flight departed from the gate 5 min before scheduled departure time. Refund options

Why complex landing gears are used instead of simple,reliability and light weight muscle wire or shape memory alloys?



Is it possible for an event A to be independent from event B, but not the other way around?



Announcing the arrival of Valued Associate #679: Cesar Manara
Planned maintenance scheduled April 23, 2019 at 23:30 UTC (7:30pm US/Eastern)Zero probability and impossibilityExchangeable Random Variable but not independent?Probability of being away from mean for independent random variablesAn example of two random variables that are mean independent but not independentCalculating probability when order matters only sometimesIf X is independent to Y and Z, does it imply that X is independent to YZ ?Representing pairwise-independent but not independent occurrences with venn diagramPairwise independent events but not mutually independentExamples of situation in which two events are independent but one event can be predicted perfectly once we know if the other happened or not.Suppose $A $ and $B$ are independent events. For an event $C $ such that $P(C) > 0$ , prove that the event of $A$ given $C $










1












$begingroup$


I was wondering, if event $A$ is independent from event $B$, would $B$ also be independent of event $A$? My original thought was that it should be independent, but then I realized if $A$ is independent from $B$ then we have: $$P(A|B)=P(A)label1tag1$$ and for $B$ to be independent from $A$ we need to have: $$P(B|A)=P(B)label2tag2$$ but in $ref1$ if $P(A)=0$ then $ref2$ doesn't make sense, so then $B$ wouldn't be independent from $A$?



Thank you










share|cite|improve this question







New contributor




Mashpa is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$
















    1












    $begingroup$


    I was wondering, if event $A$ is independent from event $B$, would $B$ also be independent of event $A$? My original thought was that it should be independent, but then I realized if $A$ is independent from $B$ then we have: $$P(A|B)=P(A)label1tag1$$ and for $B$ to be independent from $A$ we need to have: $$P(B|A)=P(B)label2tag2$$ but in $ref1$ if $P(A)=0$ then $ref2$ doesn't make sense, so then $B$ wouldn't be independent from $A$?



    Thank you










    share|cite|improve this question







    New contributor




    Mashpa is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.







    $endgroup$














      1












      1








      1





      $begingroup$


      I was wondering, if event $A$ is independent from event $B$, would $B$ also be independent of event $A$? My original thought was that it should be independent, but then I realized if $A$ is independent from $B$ then we have: $$P(A|B)=P(A)label1tag1$$ and for $B$ to be independent from $A$ we need to have: $$P(B|A)=P(B)label2tag2$$ but in $ref1$ if $P(A)=0$ then $ref2$ doesn't make sense, so then $B$ wouldn't be independent from $A$?



      Thank you










      share|cite|improve this question







      New contributor




      Mashpa is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.







      $endgroup$




      I was wondering, if event $A$ is independent from event $B$, would $B$ also be independent of event $A$? My original thought was that it should be independent, but then I realized if $A$ is independent from $B$ then we have: $$P(A|B)=P(A)label1tag1$$ and for $B$ to be independent from $A$ we need to have: $$P(B|A)=P(B)label2tag2$$ but in $ref1$ if $P(A)=0$ then $ref2$ doesn't make sense, so then $B$ wouldn't be independent from $A$?



      Thank you







      probability-theory independence






      share|cite|improve this question







      New contributor




      Mashpa is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.











      share|cite|improve this question







      New contributor




      Mashpa is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.









      share|cite|improve this question




      share|cite|improve this question






      New contributor




      Mashpa is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.









      asked 2 hours ago









      MashpaMashpa

      273




      273




      New contributor




      Mashpa is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.





      New contributor





      Mashpa is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.






      Mashpa is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.




















          3 Answers
          3






          active

          oldest

          votes


















          3












          $begingroup$

          $P(A mid B) = P(A)$ should not be taken as the definition of independence, $P(A cap B) = P(A)P(B)$ should be taken as the definition of independence. From this we can prove $P(A mid B) = P(A)$ as a corollary, provided that $P(B) > 0$.






          share|cite|improve this answer









          $endgroup$




















            3












            $begingroup$

            $P(A|B)=P(A)$ is not the correct definition of independence. The correct definition is $P(Acap B)=P(A)P(B)$. These definitions are equivalent if $P(B)>0$. With the correct definition there is symmetry between $A$ and $B$ so $A$ independent of $B$ is same as $B$ independent of $A$






            share|cite|improve this answer









            $endgroup$




















              3












              $begingroup$

              $P(Bmid A)$ is undefined when $P(A)=0$, so you can’t draw any conclusions about independence of the two events from it. That one reason why (despite what the Wikipedia page on conditional probability might imply) the fundamental definition of independence of two events uses their joint probability: $A$ and $B$ are independent iff $P(Acap B)=P(A)P(B)$. This definition is symmetric.






              share|cite|improve this answer









              $endgroup$













                Your Answer








                StackExchange.ready(function()
                var channelOptions =
                tags: "".split(" "),
                id: "69"
                ;
                initTagRenderer("".split(" "), "".split(" "), channelOptions);

                StackExchange.using("externalEditor", function()
                // Have to fire editor after snippets, if snippets enabled
                if (StackExchange.settings.snippets.snippetsEnabled)
                StackExchange.using("snippets", function()
                createEditor();
                );

                else
                createEditor();

                );

                function createEditor()
                StackExchange.prepareEditor(
                heartbeatType: 'answer',
                autoActivateHeartbeat: false,
                convertImagesToLinks: true,
                noModals: true,
                showLowRepImageUploadWarning: true,
                reputationToPostImages: 10,
                bindNavPrevention: true,
                postfix: "",
                imageUploader:
                brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
                contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
                allowUrls: true
                ,
                noCode: true, onDemand: true,
                discardSelector: ".discard-answer"
                ,immediatelyShowMarkdownHelp:true
                );



                );






                Mashpa is a new contributor. Be nice, and check out our Code of Conduct.









                draft saved

                draft discarded


















                StackExchange.ready(
                function ()
                StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3195328%2fis-it-possible-for-an-event-a-to-be-independent-from-event-b-but-not-the-other%23new-answer', 'question_page');

                );

                Post as a guest















                Required, but never shown

























                3 Answers
                3






                active

                oldest

                votes








                3 Answers
                3






                active

                oldest

                votes









                active

                oldest

                votes






                active

                oldest

                votes









                3












                $begingroup$

                $P(A mid B) = P(A)$ should not be taken as the definition of independence, $P(A cap B) = P(A)P(B)$ should be taken as the definition of independence. From this we can prove $P(A mid B) = P(A)$ as a corollary, provided that $P(B) > 0$.






                share|cite|improve this answer









                $endgroup$

















                  3












                  $begingroup$

                  $P(A mid B) = P(A)$ should not be taken as the definition of independence, $P(A cap B) = P(A)P(B)$ should be taken as the definition of independence. From this we can prove $P(A mid B) = P(A)$ as a corollary, provided that $P(B) > 0$.






                  share|cite|improve this answer









                  $endgroup$















                    3












                    3








                    3





                    $begingroup$

                    $P(A mid B) = P(A)$ should not be taken as the definition of independence, $P(A cap B) = P(A)P(B)$ should be taken as the definition of independence. From this we can prove $P(A mid B) = P(A)$ as a corollary, provided that $P(B) > 0$.






                    share|cite|improve this answer









                    $endgroup$



                    $P(A mid B) = P(A)$ should not be taken as the definition of independence, $P(A cap B) = P(A)P(B)$ should be taken as the definition of independence. From this we can prove $P(A mid B) = P(A)$ as a corollary, provided that $P(B) > 0$.







                    share|cite|improve this answer












                    share|cite|improve this answer



                    share|cite|improve this answer










                    answered 2 hours ago









                    bitesizebobitesizebo

                    1,78828




                    1,78828





















                        3












                        $begingroup$

                        $P(A|B)=P(A)$ is not the correct definition of independence. The correct definition is $P(Acap B)=P(A)P(B)$. These definitions are equivalent if $P(B)>0$. With the correct definition there is symmetry between $A$ and $B$ so $A$ independent of $B$ is same as $B$ independent of $A$






                        share|cite|improve this answer









                        $endgroup$

















                          3












                          $begingroup$

                          $P(A|B)=P(A)$ is not the correct definition of independence. The correct definition is $P(Acap B)=P(A)P(B)$. These definitions are equivalent if $P(B)>0$. With the correct definition there is symmetry between $A$ and $B$ so $A$ independent of $B$ is same as $B$ independent of $A$






                          share|cite|improve this answer









                          $endgroup$















                            3












                            3








                            3





                            $begingroup$

                            $P(A|B)=P(A)$ is not the correct definition of independence. The correct definition is $P(Acap B)=P(A)P(B)$. These definitions are equivalent if $P(B)>0$. With the correct definition there is symmetry between $A$ and $B$ so $A$ independent of $B$ is same as $B$ independent of $A$






                            share|cite|improve this answer









                            $endgroup$



                            $P(A|B)=P(A)$ is not the correct definition of independence. The correct definition is $P(Acap B)=P(A)P(B)$. These definitions are equivalent if $P(B)>0$. With the correct definition there is symmetry between $A$ and $B$ so $A$ independent of $B$ is same as $B$ independent of $A$







                            share|cite|improve this answer












                            share|cite|improve this answer



                            share|cite|improve this answer










                            answered 2 hours ago









                            Kavi Rama MurthyKavi Rama Murthy

                            76.4k53370




                            76.4k53370





















                                3












                                $begingroup$

                                $P(Bmid A)$ is undefined when $P(A)=0$, so you can’t draw any conclusions about independence of the two events from it. That one reason why (despite what the Wikipedia page on conditional probability might imply) the fundamental definition of independence of two events uses their joint probability: $A$ and $B$ are independent iff $P(Acap B)=P(A)P(B)$. This definition is symmetric.






                                share|cite|improve this answer









                                $endgroup$

















                                  3












                                  $begingroup$

                                  $P(Bmid A)$ is undefined when $P(A)=0$, so you can’t draw any conclusions about independence of the two events from it. That one reason why (despite what the Wikipedia page on conditional probability might imply) the fundamental definition of independence of two events uses their joint probability: $A$ and $B$ are independent iff $P(Acap B)=P(A)P(B)$. This definition is symmetric.






                                  share|cite|improve this answer









                                  $endgroup$















                                    3












                                    3








                                    3





                                    $begingroup$

                                    $P(Bmid A)$ is undefined when $P(A)=0$, so you can’t draw any conclusions about independence of the two events from it. That one reason why (despite what the Wikipedia page on conditional probability might imply) the fundamental definition of independence of two events uses their joint probability: $A$ and $B$ are independent iff $P(Acap B)=P(A)P(B)$. This definition is symmetric.






                                    share|cite|improve this answer









                                    $endgroup$



                                    $P(Bmid A)$ is undefined when $P(A)=0$, so you can’t draw any conclusions about independence of the two events from it. That one reason why (despite what the Wikipedia page on conditional probability might imply) the fundamental definition of independence of two events uses their joint probability: $A$ and $B$ are independent iff $P(Acap B)=P(A)P(B)$. This definition is symmetric.







                                    share|cite|improve this answer












                                    share|cite|improve this answer



                                    share|cite|improve this answer










                                    answered 2 hours ago









                                    amdamd

                                    32k21053




                                    32k21053




















                                        Mashpa is a new contributor. Be nice, and check out our Code of Conduct.









                                        draft saved

                                        draft discarded


















                                        Mashpa is a new contributor. Be nice, and check out our Code of Conduct.












                                        Mashpa is a new contributor. Be nice, and check out our Code of Conduct.











                                        Mashpa is a new contributor. Be nice, and check out our Code of Conduct.














                                        Thanks for contributing an answer to Mathematics Stack Exchange!


                                        • Please be sure to answer the question. Provide details and share your research!

                                        But avoid


                                        • Asking for help, clarification, or responding to other answers.

                                        • Making statements based on opinion; back them up with references or personal experience.

                                        Use MathJax to format equations. MathJax reference.


                                        To learn more, see our tips on writing great answers.




                                        draft saved


                                        draft discarded














                                        StackExchange.ready(
                                        function ()
                                        StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3195328%2fis-it-possible-for-an-event-a-to-be-independent-from-event-b-but-not-the-other%23new-answer', 'question_page');

                                        );

                                        Post as a guest















                                        Required, but never shown





















































                                        Required, but never shown














                                        Required, but never shown












                                        Required, but never shown







                                        Required, but never shown

































                                        Required, but never shown














                                        Required, but never shown












                                        Required, but never shown







                                        Required, but never shown







                                        Popular posts from this blog

                                        名間水力發電廠 目录 沿革 設施 鄰近設施 註釋 外部連結 导航菜单23°50′10″N 120°42′41″E / 23.83611°N 120.71139°E / 23.83611; 120.7113923°50′10″N 120°42′41″E / 23.83611°N 120.71139°E / 23.83611; 120.71139計畫概要原始内容臺灣第一座BOT 模式開發的水力發電廠-名間水力電廠名間水力發電廠 水利署首件BOT案原始内容《小檔案》名間電廠 首座BOT水力發電廠原始内容名間電廠BOT - 經濟部水利署中區水資源局

                                        Prove that NP is closed under karp reduction?Space(n) not closed under Karp reductions - what about NTime(n)?Class P is closed under rotation?Prove or disprove that $NL$ is closed under polynomial many-one reductions$mathbfNC_2$ is closed under log-space reductionOn Karp reductionwhen can I know if a class (complexity) is closed under reduction (cook/karp)Check if class $PSPACE$ is closed under polyonomially space reductionIs NPSPACE also closed under polynomial-time reduction and under log-space reduction?Prove PSPACE is closed under complement?Prove PSPACE is closed under union?

                                        Is my guitar’s action too high? Announcing the arrival of Valued Associate #679: Cesar Manara Planned maintenance scheduled April 23, 2019 at 23:30 UTC (7:30pm US/Eastern)Strings too stiff on a recently purchased acoustic guitar | Cort AD880CEIs the action of my guitar really high?Μy little finger is too weak to play guitarWith guitar, how long should I give my fingers to strengthen / callous?When playing a fret the guitar sounds mutedPlaying (Barre) chords up the guitar neckI think my guitar strings are wound too tight and I can't play barre chordsF barre chord on an SG guitarHow to find to the right strings of a barre chord by feel?High action on higher fret on my steel acoustic guitar