1. Which of the following is INCORRECT:
Independent random samples arise when ...
a. one random sample is split into groups differing by an observed feature
b. the individuals in a sample are randomly assigned to experimental groups
c. data is recorded repeatedly on a random sample of individuals
d. random samples are selected separately
2. The margin of error of a confidence interval about the difference between the means of two populations is equal to
a. half the width of the confidence interval
b. twice the width of the confidence interval
c. the width of the confidence interval
d. 1.5 times the width of the confidence interval