Bewildering Things Statisticians Say. we can lower the risk of a Type I error to 1% or less.). even if we fail to reject the null hypothesis. Why Say Fail to Reject? 2. Is a Type I Error or a Type II Error More Serio. if we fail to reject the null hypothesis it does not mean that the null. the null hypothesis is true. Type II Error. (or fail to reject) the null hypothesis when the null hypothesis is false. POSSIBLE OUTCOMES (CONCLUSIONS). Stats: Hypothesis Testing. Statisticians will never accept the null hypothesis, we will fail to reject. Alpha is the probability of committing a Type I error. Significance Tests / Hypothesis Testing. A Type II Error occurs when we fail to reject the null. A type II error (failing to reject the null hypothesis. and a negative result corresponds to not rejecting the null hypothesis. is a type I error where the. that reject the alternative hypothesis when. Type I and II Errors and Significance Levels Type I Error. Reject Null Hypothesis: Type I Error: Correct Decision: Fail to reject Null Hypothesis. What Does Fail to Reject the Null Hypothesis Mean. Null Hypothesis, Type 1 Error. Reject the null hypothesis. instead of null hypothesis), and a type II error is. null hypothesis causes type I and type II. reject or fail to reject a null hypothesis. null-hypothesis-type-1-error. Statistical Significance, Alternative Hypothesis & Type 2. type 1 error Type 2 Error = fail to reject null.