Which of the following two statements is correct?

I.A typical example of independent samples occurs when we havebefore-and-after measures of the same individuals.

II. When the population standard deviations are unknown and assumedto be equal, pooling the sample standarddeviations into a single estimate of their common population value is no longer applicable.

a.Neither I nor II.

b.Both I and II.

c.II but not I.

d.I but not II.

2.In testingthe difference between two population means using twoindependent samples, the sampling distribution of the sample mean difference₁₂is normal if the

a.sample sizes are both greater than 30.

b.population variances are known and any of the other statements is true.

c.populations are non-normal and the sample sizes are large.

d.populations are normal.

1. 3.An advantage of the p-value method over the test-statistic method in hypothesis testing is that
2. a.The p-value tells us how unlikely is the occurrence of the outcome obtained from our sample.
3. b.The p-value computations are much simpler than the test-statistic computations.
4. c.The p-value method is simpler because we can just compare the magnitudes of two values located on the horizontal axis.
5. d.The p-value method will reject the null hypothesis more often than the test-statistic method, thus reducing the chance of a Type I error.
6. e.the information for computing the p-value when the t-distribution is used is more readily available.