做了个梦：期末考前从零开始突击概率论，感觉大概率要挂科了，又急又慌 居然在梦中回忆起了卡方分布的密度函数的大致样子，这玩意儿我都多少年没碰了
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居然在梦中回忆起了卡方分布的密度函数的大致样子，这玩意儿我都多少年没碰了 
居然在梦中回忆起了卡方分布的密度函数的大致样子，这玩意儿我都多少年没碰了 