Select the best answer. Vigorous exercise helps people live several years longer (on average). Whether mild activities like slow walking extend life is not clear. Suppose that the added life expectancy from regular slow walking is just 2 months. A statistical test is more likely to find a significant increase in mean life expectancy if (a) it is based on a very large random sample and a 5% significance level is used.(b) it is based on a very large random sample and a 1% significance level is used. (c) it is based on a very small random sample and a 5% significance level is used. (d) it is based on a very small sample and a 1% significance level is used. (e) the size of the sample doesn't have any effect on the significance of the test.