A probability distribution stands that the addition of all the probabilities presented in the distribution must be equal to 1.
According to this the missing value when x is equal to 6, should be the substraction of 1 and the rest of the probabilities from the distribution
[tex]\begin{gathered} P(x=6)=1-0.28-0.28-0.3 \\ P(x=6)=1-0.86 \\ P(x=6)=0.14 \end{gathered}[/tex]
