I Really Need Help With A Few Statistic Questions!!?

I’m really struggling in statistics class and I need help!
4. Vigorous exercise helps people live several years longer (on the average). Whether mild activities like slow walking extend life is not clear. Suppose that the additional life expectancy from regular slow walking is just 2 months. A statistical test is more likely to find a significant increase in mean life if
(A) it is based on a very small random sample
(B) the p-value is large
(C) the test of hypotheses is not rejected
(D) it is based on a very large random sample
(E) The size of the sample doesn’t have any effect on the significance of the test.
Use the following for the next 3 questions
Is caffeine dependence real? A study was conducted with 8 individuals diagnosed as being dependent on caffeine. Each subject was barred from coffee, colas, and other substances containing caffiene. Instead, they took capsules containing thier usual caffeine intake. During a different time period they took placebo capsules. It was a blind experiment. Depression was measured after each period using the Beck Depression Invetory. Higher scores show more symptoms of depression. We have a depression score for each individual while using caffeine (Depr Caffiene) and a depression score for each individual while using the placebo (Depr Placebo)
N Mean StDeviation
Depr Placebo 8 11.3636 7.9028
Depr Caffeine 8 4.0000 3.3764
Difference P-C 8 7.3636 6.9177
6. The research question is “Are caffeine dependent people more depressed when they don’t use caffeine?” The null and alternative hypotheses of the study are:
(A) Ho: u=0 Ha: u ≠ 0
(B) Ho: u=0 Ha: u > 0
(C) Ho: p=0 Ha: p ≠ 0
(D) Ho: u=0 Ha: u < 0
(E) Ho: x̄ =0 Ha: x̄ ≠ 0
8. With a significance level of a= 0.05, we can conclude
(A) That the null will fly
(B) That there is not sufficient evidence to warrant rejection of the null hypothesis
(C) That there is not sufficient evidence to conclude that caffeine dependent people are more depressed when they don;t use caffeine
(D) That there is strong evidence to suggest that caffeine dependent people are more depressed when they don't use caffeine.
I need help! Thanks!