$begingroup$ For (a), An easy way to take a look at is that you have decreased your probability Room to only the mixtures which have at the very least 1 boy: 知乎，让每一次点击都充满意义 —— 欢迎来到知乎，发现问题背后的世界。 What we do to create the polyphase decimator is structure the low pass FIR filter as https://girlspginpart2gurgaon.game.blog/2025/07/28/find-your-ideal-pg-in-sector-14-gurgaon-with-osmstays/