When you get--this is Rituparna, counting the leaves on a tree-- you can estimate, from a sample, the population expected values.

如果你...像数叶子的睿都巴若那一样,只有部分样本的话,你可以来估计总体均值

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And the other thing you can do is take self reports like the ones you're doing, hopefully do enough of them, and a random enough sample of the population, that you can extrapolate from that sample to the whole population, and try to estimate what people are eating in that way.

还有其他可以做的,比如大家正在做的这种个体调查,希望能把它做的充分些,如果有充足的随机样本,就可以从样本推断出,整个总体,从而推断哪类人有这样的饮食习惯

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