Answer
$P(1\leq X\leq 9) = \frac{7}{8} $
Work Step by Step
number of heads = $\{ 0,1,2,3\}$
the square of the number of heads = $\{ 0^2,1^2,2^2,3^2\} = \{ 0,1,4,9\}$
X, P(X)
0 , $\frac{1}{8}$
1 , $\frac{3}{8}$
4 , $\frac{3}{8}$
9 , $\frac{1}{8}$
Therefore:
$P(1\leq X\leq 9) = P(1) + P(4) + P(9) = \frac{1}{8} + \frac{3}{8} + \frac{3}{8} = \frac{7}{8} $
