Consider an economy with two types of firms, S and I. S firms all move together. I firms move independently. For both types of firms, there is a 70% probability that the firms will have a 7% return and a 30% probability that the firms will have a -18% return. What is the volatility (standard deviation) of a portfolio that consists of an equal investment in 35 firms of

(a) type S

(b) type I?