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0。模型给出了最好的条件均值，却没有给出一个真实可能样本。对应图像的直观例子是杯子可能在左或右，逐像素平均可能出现模糊或重影，而不是某一次合理摆放。","sha256":"ec82615f31363bf1381e632f8e55f0353c2518e887115e94bbcef18d3f97b078","chapter":{"id":"III","title":"视觉与语言"},"unit":{"id":"generation-many-possible-results","title":"一个条件怎样容纳多种合理结果？"},"page":{"id":"reading-opening","title":"一个可算的多解例子：最小均方误差为何给出不存在的结果","number":1},"sectionTitle":"一个可算的多解例子：最小均方误差为何给出不存在的结果","currentQuestion":"一个可算的多解例子：最小均方误差为何给出不存在的结果","sourceSlides":[],"knowledgeBlock":null,"formulas":[{"latex":"a=0","definitionContext":"一个可算的多解例子：最小均方误差为何给出不存在的结果"}],"previousBlock":"b-8732ad587e32b3571403d945","nextBlock":"b-134c77589114459428593887","prerequisites":[{"id":"b-e32d8e8491c390884be822ae","url":"#b-e32d8e8491c390884be822ae","role":"section-title"},{"id":"b-cbfbd6e975a2f4e99daa7376","url":"#b-cbfbd6e975a2f4e99daa7376","role":"problem-context"}],"relatedBlocks":[]},{"id":"b-134c77589114459428593887","type":"p","scope":"conditional-mean-is-not-sample","url":"https://codingai-lec03.pages.dev/course/blocks/conditional-mean-is-not-sample.html#b-134c77589114459428593887","content":"再设生成器正确地随机输出 $-1$ 或 $+1$，与一份独立抽出的真值比较，二者一半相同、一半差 2，期望平方误差是 $0.5\\times0+0.5\\times4=2$。生成器符合真实分布，却在这种独立配对 MSE 上比输出 0 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继续阅读与实验","sha256":"2b9ccef7e1220e2250cceff1abd8bdd736b42f8da5a223f26b029f44b962e807","chapter":{"id":"III","title":"视觉与语言"},"unit":{"id":"generation-many-possible-results","title":"一个条件怎样容纳多种合理结果？"},"page":{"id":"reading-opening","title":"一个可算的多解例子：最小均方误差为何给出不存在的结果","number":1},"sectionTitle":"一个可算的多解例子：最小均方误差为何给出不存在的结果","currentQuestion":"一个可算的多解例子：最小均方误差为何给出不存在的结果","sourceSlides":[],"knowledgeBlock":null,"formulas":[],"previousBlock":"b-4eca5e1f702dd1820149e419","nextBlock":null,"prerequisites":[{"id":"b-e32d8e8491c390884be822ae","url":"#b-e32d8e8491c390884be822ae","role":"section-title"},{"id":"b-cbfbd6e975a2f4e99daa7376","url":"#b-cbfbd6e975a2f4e99daa7376","role":"problem-context"}],"relatedBlocks":[]}]}