to Huff, "The dependability of a sample can be destroyed by [bias]... allow yourself some degree of skepticism." To assist in the understanding of statistics Huff proposed a series of questions to be asked in each case: Who says so? (Does he/she have an axe to grind?) How does he/she know? (Does he/she have the resources to know the facts?) What's missing? (Does he/she give us a complete picture?) Did someone change the subject? (Does he/she offer us the right answer to the wrong problem?) Does it make sense? (Is his/her conclusion logical and consistent with what we already know?) Misinterpretation: correlation The concept of correlation is particularly noteworthy for the potential confusion it can cause. Statistical analysis of a data set often reveals that two variables (properties) of the population under consideration tend to vary together, as if they were connected. For example, a study of annual income that also looks at age of death might find that poor people tend to have shorter lives than affluent people. The two variables are said to be correlated; however, they may or may not be the cause of one another. The correlation phenomena could be caused by a third, previously unconsidered phenomenon, called a lurking variable or confounding variable. For this reason, there is no way to immediately infer the existence of a causal relationship between the two variables. Applications Applied statistics, theoretical statistics and mathematical statistics Applied statistics, sometimes referred to as Statistical science, comprises descriptive statistics and the application of inferential statistics. Theoretical statistics concerns the logical arguments underlying justification of approaches to statistical inference, as well as encompassing mathematical statistics. Mathematical statistics includes not only the manipulation of probability distributions necessary for deriving results related to methods of estimation and inference, but also various aspects of computational statistics and the design of experiments. Statistical consultants can help organizations and companies that don't have in-house expertise relevant to their particular questions. Machine learning and data mining Machine learning models are statistical and probabilistic models that capture patterns in the data through use of computational algorithms. Statistics in academia Statistics is applicable to a wide variety of academic disciplines, including natural and social sciences, government, and business. Business statistics applies statistical methods in econometrics, auditing and production and operations, including services improvement and marketing research. A study of two journals in tropical biology found that the 12 most frequent statistical