In testing whether the means of two normal populations are equal, summary statistics computed for two independent samples are as follows:
brand x n2=20 xbar 2=6.80 s2=1.15
brand y n1=20 xbar1=7.30 s1=1.10
assume that the population variances are equal. then, the standard error of the sampling distribution of the sample mean difference xbar1−xbar2 is equal to: question 2 options: (a) 1.1275 (b) 0.1266 (c) 1.2663 (d) 0.3558.