Answer
No, razor type and rating are not independent
Work Step by Step
According to item (a): $P(Excellent)=\frac{53}{90}$
According to item (d): $P(Excellent~|~C)=\frac{13}{30}=\frac{39}{90}$
$P(Excellent~|~C)\ne P(Excellent)$. We can also verify that:
$P(C~|~Excellent)\ne P(C)$.
Razor type and rating are not independent. See the definition on page 292.
