Test the null hypothesis that the means from two populations are equal in the following case. 1 and 2 are sample means found from samples with size n1 and n2 drawn from normal distributions with known variances σ21 and σ22. State the significance level of the test. Use a two-tailed test.
1 = 20.0, 2 = 21.0, n1 = 25, n2 = 50, σ21 = 25.0, σ22 = 25.0.