Match the following.

List-I	List-II
a. $${\beta _1}$$	1. $${\beta _2} - 3$$
b. $${\beta _2}$$	2. $$\frac{{\mu _3^2}}{{\mu _2^3}}$$
c. $${\gamma _1}$$	3. $$\frac{{{\mu _4}}}{{\mu _2^2}}$$
d. $${\gamma _2}$$	4. $$\sqrt {{\beta _1}} $$