Consider the following data drawn independently from normally distributed populations: (You may find it useful to reference the appropriate table: z table or t table)

x1x1 = 11.9	x2x2 = 17.8
s12 = 7.2	s22 = 7.7
n1 = 17	n2 = 27

a. Construct the 90% confidence interval for the difference between the population means. Assume the population variances are unknown but equal. (Round final answers to 2 decimal places.)