A few years ago, a report in Lancet indicated that several people in New Mexico had succumbed to a rare disease, eosinophilia-myalgia syndrome (EMS). The only circumstance they seemed to have in common was that they had taken large quantities of an amino acid health food called tryptophan (tryptophan ingestion). Through investigation, a number of people were found throughout the country that had a diagnosis of EMS (development of EMS). The question was asked, was there a statistically significant relationship between ingesting tryptophan and developing EMS? (alpha = .05) Tryptophan Yes EMS No EMS
Yes Cell A 20 Cell C 18
No Cell B 17 Cell D 38
What is the level of measurement for the variable ‘tryptophan ingestion’?
a) Nominal
b) Ordinal
c) Interval
d) Ratio