Consider the following competing hypotheses and accompanying sample data drawn independently from normally distributed populations. (You may find it useful to reference the appropriate table: z table or t table) H₀: _{1 2} 0 H_A: _{1 2} < 0

x1x1 = 257	x2x2 = 261
s1 = 34	s2 = 20
n1 = 7	n2 = 7

a-1. Calculate the value of the test statistic under the assumption that the population variances are equal. (Negative value should be indicated by a minus sign. Round final answer to 3 decimal places.)

Calculate the value of the test statistic under the assumption that the population variances are unknown and are not equal. (Negative value should be indicated by a minus sign. Round final answer to 3 decimal places.)