# Reject null hypothesis test, can we accept the null hypothesis?

The outcomes that would tend to refuse this null hypothesis are those with a large number of heads or a large number of tails, and our experiment with 5 heads would seem to belong to this two sided null hypothesis. A Type I error occurs when the researcher rejects a null hypothesis when it is true.

Failure to reject implies that the data are not sufficiently persuasive for us to prefer the alternative hypothesis over the null hypothesis. A statistical hypothesis is an assumption about a population parameter. This section is too long.

The directionality of hypotheses is not always obvious. Moreover, some users of statistics argue that we should always work with the two-sided alternative.

Fisher published the first edition of the book " The Design of Experiments " which introduced the null hypothesis [20] by example rather than by definition and carefully explained the rationale for significance tests in the context of the interpretation of experimental results; see The Design of Experiments Quotations regarding the null hypothesis. Hence, under this two-tailed null hypothesis, the observation receives a probability value of 0.