e****i
发帖数: 78 | 1 请教一个问题， 如果create a small sample (100 obs) from a bigger sample (
30000 obs) and the mean of small sample not equal to bigger sample. 具体来说
， bigger sample's mean = 100, 如果create a small sample (100 obs) with mean
equal to 145?
多谢！ |
n**********0
发帖数: 66 | 2 不懂你的意思。如果mean差那么大，那你就不可能是random sample也不
representative了吧。如果你是有bias的选择，那怎么着都行了 |
t*****a
发帖数: 459 | 3 为什么用mean来评价？确定是normal distribution? |
g******2
发帖数: 234 | 4 I guess you are talking about truncated distribution. Find a threshold T
such that E(X|X>T)=145, and then sample 100 points from X|X>T. |
