Question

1.         The minimum probability of rejecting the null hypothesis that is most acceptable in the field of science is .05. Why are researchers generally less willing to raise the probability of rejecting the null hypothesis to levels that are greater than .05?

Answer 1

The level of significance is , that is defined as the probability of discarding the null hypothesis given the fact that it was actually correct. It is also known as Type-1 Error and this value is always fixed in advance in case of hypothesis testing and interval estimation. Mathematically:

When , this implies that there is 5% chance of rejecting a correct null hypothesis. The type-1 errors are to be dealt with utmost care because it implies the probability of declining a true null hypothesis and hence making incorrect inferences about the population. Thus, if the researchers raise the value of , it would mean that a greater percentage of correct null hypothesis are being rejected and hence a greater number of incorrect inferences about the population are being stated.

Hence, increasing the value of type-1 error, that is, is not favorable.