Final answer:
A small sample size and a large standard deviation make the sample mean an extreme, unrepresentative value for the population.
Step-by-step explanation:
In order for the sample mean to be an extreme, unrepresentative value for the population, the sample size should be small and the standard deviation should be large. For example, if the sample size is only 10 and the standard deviation is 20, the sample mean could be significantly different from the population mean.
However, if the sample size is large, such as 100, and the standard deviation is small, the sample mean is more likely to be representative of the population mean.