Which is an example of how bacteria help keep the environment clean?
They can reduce oxygen in the air.
They can decompose waste.
They can help develop medicines.
They can slow digestion.

Aresearcher created three groups based on participants bmi: normal weight, overweight and obese. the hypothesis being tested is that the three groups differ in the mean number of artificially sweetened drinks consumed weekly. which statistical test might the researcher use, assuming a reasonably normal distribution of values.