For each scenario presented below, state whether the research study is an experiment or a quasi-experiment. In addition, explain the characteristics of the study that either make it an experiment or make it a quasi-experiment.

A. A researcher wants to know if drinking caffeine helps students get better grades on a math exam. He randomly assigns students to two groupsone that he gives caffeine to drink and one that he does not. Then he gives each participant a math exam.

B. A study is done to investigate type of office chairs and productivity. The participants are from two teams of claims processors for a local insurance agency. The members of one team are given a new chair with extra cushioning and adjustable height and lumbar support. Members of the other team, the control group, continue to use the current chair made from moldable plasticergonomically shaped but with no frills.

C. A researcher uses random sampling to recruit 200 pregnant women between 2 and 3 months along in their pregnancy for a study investigating the effects of prenatal stress on perinatal APGAR scores (i.e., newborn's heartrate, breathing, muscle tone, reflex response, and color). Once recruited, the researcher assigns the pregnant women to two groups by administering a brief stress survey and placing those with the highest scores (i.e., most stress) in the treatment group and those with the lowest scores in the nontreatment group. The treatment group receives a home visit and brief coping skills intervention once each month to check the mother's health and provide evidence-based strategies for reducing stress. The non-treatment group receives only the home visit each month as a health check.