Chapter 4 - Discrete Random Variables - Exercises 4.50 - 4.76 - Applying the Concepts - Basic - Page 205: 4.62d

$p(x=7)=0.117$

$q=1-p=1-.5=.5$ $p(x)=\begin{pmatrix} n \\ x \end{pmatrix}p^xq^{n-x}$ $p(x=7)=\begin{pmatrix} 10 \\ 7 \end{pmatrix}(.5)^7(.5)^{10-7}=\frac{10!}{7!(10-7)!}(.5)^{10}=\frac{10(9)(8)(7!)}{7!(3!)}(.5)^{10}=0.117$