Answer
See below.
Work Step by Step
a) $P(tropical \ storm)=\frac{\text{number of tropical storms}}{\text{total number of cyclones}}=\frac{598}{1575}\approx0.38$
b) $P(tropical \ storm|Southern \ hemisphere)=\frac{\text{number of tropical storms in Southern hemisphere}}{\text{total number of cyclones in Southern hemisphere}}=\frac{200}{433}\approx0.462$
