Determine whether the description corresponds to an observational study or an experiment. Research is conducted to determine if there is a relation between stomach cancer and alcohol consumption.

Observational

Step-by-step explanation:

Observational studies are studies that measure the outcome of events without the introduction of interventions. They are useful in the formation of a hypothesis. The experiment described above is an observational study that compares two groups so as to measure the predictors of an outcome. No intervention is introduced to influence the outcome of the research.

An experiment on the other hand is often organized as a randomized control trial where subjects are divided into groups and a placebo or control group is introduced to monitor the outcome of the study.

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step-by-step explanation:

if the four friends split the cost, p, of the pizza evenly, then each friend pays one-fourth of the cost of the pizza.

the expression is   or