Take the tour ×  Given Data :  Normal Distribution function
$$P(x \leq -1) = P(y \geq 2)$$  x : mean= 1 variance= 4  y :
mean= -1 variance= to be found..?.  Ans: 9  How to solve..?
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down vote accepted  Firstly,
$P(x\le-1)=\Phi\left(\frac{-1-1}{\sqrt4}\right)=\Phi(-1)$ Also, 
$P(y\ge2)=P(y\le-4)=\Phi\left(\frac{-4-(-
1)}{\sigma}\right)=\Phi\left(\frac{-3}{\sigma}\right)$.  So we
have $\frac{-3}{\sigma}=-1$ and $\sigma^2=9$.  share|improve
this answer Thank you............:) –  Jay Satish Teli Feb 9 at
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