Select from the drop-down list, the correct test to use for the given scenario.

a)A horticulturalist is interested in which of two different new varieties of broad bean produces the highest average yield. She grows forty plants of each of the two varieties in her company's research garden and measures the yield of beans (in grams) from each plant.

Choose...

One-sample z-test

Matched-pairs t-test

One-sample t-test

Two-sample z-test

Two-sample t-test

b)A small clinical trial comparing two drugs (A and B) has a crossover design. The aim of the treatments is to reduce the level of a certain substance in blood, on average. Twenty patients are given one drug, and after two hours the level of the substance in their blood is measured. Three days later, the same patients are given the other drug, and again after two hours the level of the substance in their blood is measured. Half the patients get drug A first, and the others get drug B first. (You may assume that any relevant quantities have a normal distribution.

Choose...

One-sample z-test

Matched-pairs t-test

One-sample t-test

Two-sample z-test

Two-sample t-test