Beware that, in this context, the word "tail" takes two meanings: either as outcome of a single toss, or as region of extremal values in a probability distribution. The one-tailed nature of the test resulted from the one-tailed alternate hypothesis a term not used by Fisher.

She has taught science courses at the high school, college, and graduate levels.

How do we know which hypothesis is the null and which one is the alternative? Because that's what the drink machine is supposed to do. A significance test is used to determine the likelihood that the results supporting the null hypothesis are not due to chance.

The null hypothesis is the initial statistical claim that the population mean is equivalent to the claimed. This raises the question how we can ever say anything about our population if we only have a tiny sample from it. It eliminates the issues surrounding directionality of hypotheses by testing twice, once in each direction and combining the results to produce three possible outcomes.

Following: Fisher and Neyman quarreled over the relative merits of their competing formulations until Fisher's death in Hypothesis Testing for Investments As an example related to financial markets, assume Alice sees that her investment strategy produces higher average returns than simply buying and holding a stock.

Poor statistical reporting practices have contributed to disagreements over one-tailed tests.

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Null hypothesis