+157 The mean mark on a state-administered mathematics exam by a 10th grade class in Smalltown, Wisconsin, was 95%, while the mean mark on the same exam by 10th grade students in the entire state of Wisconsin was reported to be only 78%. This suggests that the mean can be __________.
A. a parameter or a statistic
B. a parameter only
C. a statistic only
D neither a parameter nor a statistic
