Suppose you are conducting a test of significance in the following situations. For each of these, determine whether you should conduct a one-proportion z-test or a two-proportion z-test. 

a. You want to test to see whether children and adults differ in terms of which type of chocolate they prefer (milk chocolate or dark chocolate). You find that 70% of the adults prefer dark chocolate and only 24% of the children prefer dark chocolate. 

b. You want to test to see whether people prefer milk chocolate or dark chocolate and find that 62% of your sample prefers dark chocolate and the other 38% prefers milk chocolate.