Of all of the amino acids only 9 are essential and .

can only be obtained from the food you eat
can only be found in protein supplements
can be found in vitamin supplements
are found normally in the body and not needed in part of the diet

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.