Question

8.	A fish-oil manufacturer believes its product can boost mental acuity. Listed below are the results of a memory exam on a group of subjects with one column measuring their performance on the exam before taking the supplement and the second measuring performance of the same individual after taking the supplement for one month. Using a 5% significance level, is there statistically sufficient evidence to support the claim that the scores were higher following one month of taking the fish-oil? Perform an appropriate hypothesis test showing necessary statistical evidence to support your conclusion.
		Before	After
		88	90
		67	71
		83	81
		79	84
		67	69			Conclusion:
		65	70
		59	63
		81	75
		70	72
		65	63

Answer 1

Ans:

	Before	After	d
1	88	90	2
2	67	71	4
3	83	81	-2
4	79	84	5
5	67	69	2
6	65	70	5
7	59	63	4
8	81	75	-6
9	70	72	2
10	65	63	-2
		d-bar=	1.4
		sd=	3.627

Test statistic:

t=(1.4-0)/(3.627/SQRT(10))

t=1.221

df=10-1=9

p-value=tdist(1.221,9,1)=0.1266

As,p-value>0.05,we fail to reject the null hypothesis.

There is not sufficient evidence to support the claim that the scores were higher following one month of taking the fish-oil.