Study of 400 patient in a Wuhan city revealed that if they visited the popular bat market the sample in this study is out of Select one: O a. the patient in a Wuhan city question O b. the popular bat market O c. all the people in Wuhan city O d. 400 patient in a Wuhan city 10 The variable "Grade levels in a university (A, B, C, D, F)" is: Select one: put of O a. Interval O b. Nominal uestion O c. Ratio O d. Ordinal