1. Two sample z-test Suppose we want to know whether the mean length of unemployment differs among the residents of two local communities. Sample information is as follows: Community A: sample mean ( ) = 62.2 days Sample variance( ) = 6.2 sample size ( ) = 120 Community B: sample mean ( ) = 61.3 days sample variance ( ) =6.75 sample size ( ) = 150 Are the unemployment lengths signicantly different between two communities? Set up the null and alternative hypotheses. Perform a statistical test to answer the