uppose that when taking a random sample of thirty students' GPA, you get a sample mean of 3.9 (out of a possible 4.0). The sample mean is far higher than the collegewide (population) mean. Does this:
a) Indicate sampling bias
b) Suggest that the sample mean is unreliable
c) Suggest that the population mean may have changed
d) Indicate that the sample may not be representative of the population