{"schema_version":"ocme-site-results-v1","locale":"zh-Hant","page_type":"derivations","facts":{"questions":36000,"reviewed":36000,"display_candidates":0,"knowledge":302,"guides":299,"paths":59,"batches":360,"families":1441,"atlas":302,"core":80,"evidence":9,"formal_evidence":5,"formal_subjects":4,"lean_files":6,"lean_toolchain":"leanprover/lean4:v4.30.0","question_state":"candidate","english_state":"ai_candidate","question_Lean":"NOT_RUN","canonical_truth_promotion":false},"filters":{"q":"mko-finite-discrete-probability-distribution"},"kind":"guides","total":1,"pages":1,"page":1,"entries":[{"id":"derivation-mko-finite-discrete-probability-distribution-01","title":{"zh-Hant":"有限離散機率分布：核 PMF 資格、事件機率、期望與推前分布","en":"Finite discrete probability distribution: validating a PMF, event probability, expectation and pushforward"},"summary":{"zh-Hant":"隨機變數 X 取值 −1、0、1、2，質量 p(−1)=1/6、p(0)=1/3、p(1)=1/4、p(2)=1/4。（一）先核 p 是否為合格 PMF；（二）求 P(X≥1)；（三）求 E[X]；（四）求 Y=X² 的推前分布、證明它仍是 PMF，求 E[Y] 並以 Σx²p(x) 交叉核對；（五）判定兩個候選 q、r 不是 PMF：q 每項介於 0 與 1 但總和不為 1，r 總和為 1 但有負項。","en":"A random variable X takes the values −1, 0, 1, 2 with masses p(−1)=1/6, p(0)=1/3, p(1)=1/4, p(2)=1/4. (1) First check that p is a valid PMF; (2) find P(X≥1); (3) find E[X]; (4) find the pushforward distribution of Y=X², prove it is again a PMF, find E[Y] and cross-check it against Σx²p(x); (5) decide that two candidates q and r are not PMFs: every mass of q lies between 0 and 1 but the total is not 1, while r sums to 1 but has a negative mass."},"mko_ids":["mko-finite-discrete-probability-distribution"]}],"title":"概念推導導讀"}