A researcher wants to study the impact of a new artificial sweetener on blood glucose. Participants will have a drink either with or without the sweetener and then have their blood glucose measured.

He designs the following experiment: 100 participants each have both drinks, but on two different days. The first day, they are randomized to receive one of the drinks, and then have their glucose measured. The second day, they receive the other drink, then they have their glucose measured again. So the researcher has 200 measurements: 100 from the participants measured on the day they received the artificial sweetener, and 100 from the same participants measured on the day they received the drink without it.

Is the two-sample z test appropriate here?

A) yes, because there are two averages

B) no, because we see both glucose values for each participant

C) yes, because people are randomized to groups