Question

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 litter-mates. The rations were assigned at random to the two animals within each pair. The gains (in pounds) after 45 days are shown in the following table. Assuming weight gain is normal, find the 90% confidence interval estimate for the mean of the differences μ_d, where d = ration A - ration B. (Give your answers correct to two decimal places.)

Litter	1	2	3	4	5	6	7	8
Ration A	44	55	47	53	42	41	46	43
Ration B	40	46	42	44	33	40	43	38

Lower Limit
Upper Limit

Answer 1

for 95% CI; and 7 degree of freedom, value of t=			2.365
therefore confidence interval=sample mean -/+ t*std error
margin of errror          =t*std error=		2.565
lower confidence limit                     =		3.06
upper confidence limit                    =		8.19