Type 1 and 2 Errors

• Type I Error:

  > occurs when the researcher has used a lenient P value

  > the researcher wrongly thinks the results are significant when they are actually due to chance/error

  > they wrongly accept the alternative hypothesis and wrongly reject the null
• Type II Error:

  > occurs when the researcher has used a stringent P value

  > the researcher thinks that their results are not significant when they could be

  > they wrongly accept the null hypothesis and wrongly reject the alternative hypothesis
• To Check for a Type I Error:

  > compare the calculated value to a critical value from a more stringent P value

  > if the results are still significant, the researcher has not made a type 1 error

  > if the results are no longer significant, there is a chance of a type 1 error
• To Check for a Type II Error:

  > compare the calculated value to a critical value from a more lenient P value

  > if the results are still not significant, the researcher has not made a type II error

  > if the results are now significant, there is a chance of a type II error