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I have a presumably simple question. What does this mean: with probability 0.3 variable X is simulated as

X~N(0,1).

How can I simulate X using this?

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    $\begingroup$ What happens if the N(0,1) does not happen? A deterministic zero? $\endgroup$ Commented Feb 20, 2013 at 14:26
  • $\begingroup$ Simulate... what? The 1s and 0s that might make up X? $\endgroup$ Commented Feb 20, 2013 at 14:31
  • $\begingroup$ Well thank you both for your interest! Below richard gave exactly the point i couldnt grt. Thank you. $\endgroup$
    – Christos
    Commented Feb 20, 2013 at 15:12
  • $\begingroup$ It sounds like the analyst only has a 30% chance of being at work today. :-) More seriously, the phrase is nonsensical because it is silent about what happens the other 70% of the time--and by its construction it (bizarrely) suggests the possibility that 70% of the time a the variable won't be simulated at all! $\endgroup$
    – whuber
    Commented Feb 21, 2013 at 8:55
  • $\begingroup$ Well the exact phrase is: simulated data were generated as follows. With prob '0.3 X~N(0,1)' and with prob '0.7 X~N(y,1)' (while y is known). $\endgroup$
    – Christos
    Commented Feb 22, 2013 at 11:52

1 Answer 1

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What about first sampling a uniform $U$. If $U<0.3$ (this has probability $0.3$) then you sample $N(0,1)$ else you do something else.

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