Type I and Type II Errors
In hypothesis testing there are two possible errors we can make: Type I and Type II errors.
- A Type I error occurs when your reject a true null hypothesis (remember that when the null hypothesis is true you hope to retain it).
- A Type II error occurs when you fail to reject a false null hypothesis (remember that when the null hypothesis is false you hope to reject it).
- The best way to allow yourself to set a low alpha level (i.e., to have a small chance of making a Type I error) and to have a good chance of rejecting the null when it is false (i.e., to have a small chance of making a Type II error) is to increase the sample size.
- The key in hypothesis testing is to use a large sample in your research study rather than a small sample!
If you do reject your null hypothesis, then it is also essential that you determine whether the size of the relationship is practically significant