Cumulative distribution function question

[sneaky666]

consider rolling a die.
S= {1,2,3,4,5,6}
P(s)=1/6 for all s in S
X= number on die so that X(s)=s for all s in S
Y= X^2
compute the cumulative distribution function Fy(y) = P(Y<=y), for all y in the set of real numbers.

My guess
for Y=1 i get
P(-inf<y<=1)=P(Y<=1)-P(Y<-inf)=Fx(1)-Fx(-inf)
= Fx(1)-0
= Fx(1)

Is this all I have to do for Y=1, or do I have to integrate, or is there anything wrong?

 

[sneaky666]

EDIT: ok i figured it out but i need help on this one.

Let X~N(0,1) . Compute each in terms of function ϕ.
And evaluate it numerically.

P(X<=-5)
P(-2<=X<=7)
P(X>=3)

for the first one i get
ϕ(-5)

But how do i evaluate it?

 

[ZioX]

http://statistics.laerd.com/statistical-guides/normal-distribution-calculations.php