Truth about the population H0 TrueH1 True

Correct decision

Type II error

Type I error

Correct decision

(b) Example

Courtroom Verdict Not Guilty


Defendant Not Guilty Guilty

Correct decision

Wrongfully acquitted

Wrongfully accused

Correct decision

selected frequently. The value of 0.05 is equivalent to a 95% 'confidence limit' while a of 0.01 represents a 99% confidence limit. When we select the significance level (a) of a test, we are setting the probability of a type I error ('wrongfully accused'). Small p-values lead to rejection of the null hypothesis (and acceptance of the alternative hypothesis) while large p-values favor the null hypothesis.

The null hypothesis is rejected when the computed p-value lies in the region of rejection, which is usually p < 0.05. Rejection of the null hypothesis implies acceptance of the alternative hypothesis. When multiple analyses are being performed simultaneously for significance testing, the Bonferroni correction may be applied (D.N.A. Box 19.2).

It is important to recognize that by chance 5% of tests will have p-values below p = 0.05. Thus, just because a test of significance is below a certain value, the null hypothesis should not necessarily be rejected.

Was this article helpful?

0 0
Prevent Stuttering

Prevent Stuttering

Are You Suffering From Social Withdrawal? Do People Shun Or Ostracize You Because You Have A Hard Time Getting Some Of Your Words Out? Or Does Your Child Get Teased At School Because They Stutter And Cant Speak Like Everyone Else? If you have answered yes to any of the above, then you are in the tiny percentage of people that stutter.

Get My Free Ebook

Post a comment