When looking at statistics one should be wary of certain common types of biases: confirmation bias, sampling bias, undercoverage bias,and outlier bias. Confirmation bias occurs when the researchers have the tendency to search for, interpret, favor, and recall information in a way that confirms or supports one's prior beliefs or values. Sampling bias occurs when a sample is collected in such a way that some members of the intended population have a lower or higher sampling probability than others.Undercoverage bias occurs when some respondents of the sample population are not wholly represented. Finally, outlier bias occurs when the sample has outliers can significantly skew data.