An experiment was designed to estimate the mean difference in weight gain for pigs fed ration A as compared with those fed ration B. Eight pairs of pigs were used.The pigs within each pair were littermates.The rations were assigned at random to the two animals within each pair. The gains (in pounds) after 45 days are shown in the table at top of next column.

Assuming weight gain is normal, find the 95% confidence interval estimate for the mean of the differences md, where d = ration A - ration B

Litter Ration A 6537 40 47 49 65 53 59 Ration B5839 3 45 7 55 59 51 2 3 5 6 7