You have selected two random samples of size 50, one from Population 1 and one from Population 2. You intend to use the samples to test the following hypotheses regarding the difference in means for the two populations: H₀: μ₁ – μ₂ = 0 H_a: μ₁ – μ₂ ≠ 0 

a. Suppose the sample results are ₁ = 122 and ₂ = 115. Compute the sample test statistic, z stat. Assume the population standard deviations are σ₁ = 14 and σ₂ = 18. 

b. Using a significance level of .10, show the critical z_scores, z_cl and z_cu, for the test and state your decision rule. Report your conclusion.