Assume that the paired data came from a population that is normally distributed. Using a 0.05 significance level find the mean value of the differences d for the paired sample data, the standard deviation of the differences d for the paried sample data, the t test statistic, and the critical values to test the claim that ?d=0.
xi 15 9 19 6 6 13 18 8
yi 15 12 14 10 9 13 14 7