1) The sample statistic for a two-sample hypothesis test for difference in population means when you have paired samples is

a) the median of the differences between sample 1 and sample 2 b) the square root of the differences between sample 1 and sample 2

c) the squared mean of the differences between sample 1 and sample 2 d) the mean of the differences between sample 1 and sample 2

2) A highly precise estimate means that if you repeated the sampling and analysis many times, the estimates would be

a) within a small range of values b) within a large range of values c)centered on the true value d) the true value.

3) When two variables vary from their mean, in the same way, i.e.positive associated with positve, negative with negative)this indicates

a) positive covariance b) negative covariance c) regression d) no covariance

4) If you were going to model the counts of number of cases of a rare disease across census tracts, what probability model would be appropriate? a) Binomial b) Normal ( Gaussian) c) Poisson d) Uniform