3.

a) Using a Wilcoxon test (two-tailed), determine whether there is a statistically significant difference at = 0.01 between the # of items recalled using memory in 8 subjects, first given vitamin B12 and then a week later given a placebo (since vitamin B12 is water soluble). Be sure to clearly state the null and alternate hypotheses. [10 marks]

b) Perform a paired difference test on this data for = 0.01 (two-tailed test). Be sure to clearly state the null and alternative hypotheses.Are the results significant? [10 marks]

Vitamin B12 (# of items recalled)	Placebo (# of items recalled)
15	10
13	17
16	8
20	20
17	12
15	12
14	18
20	12