Answer: [tex]\text{P(not 3)}=0.85[/tex]
Step-by-step explanation:
The given table :
X 1 2 3 4
P(X) 0.30 0.40 0.15 0.15
From the above table we can see that [tex]P(X=3)=0.15[/tex]
Also, we know that for any event A , [tex]\text{P(not A)}=1-P(A)[/tex]
Therefore,
[tex]\text{P(not 3)}=1-P(X=3)\\\\\Rightarrow\text{P (not 3)}=1-0.15\\\\\Rightarrow\ \text{P(not 3)}=0.85[/tex]
