Biology 2244A/B Lecture Notes - Lecture 13: Type I And Type Ii Errors, Null Hypothesis, Statistical Hypothesis Testing

• School: Western University
• Department: Biology
• Course: Biology 2244A/B
• Professor: Angela White

Document Summary

Hypothesis statement about property of population. Hypothesis test procedure to test that statement. If p-value is less than alpha, the assumption is not correct. In other words, we reject the null hypothesis. Null hypothesis (h0) statement is equal to population parameter. Alternative hypothesis (ha or h1) statement is different than population parameter. Test statistics: value made from sample data. Critical region: values that cause us to reject the null hypothesis, typically small values. Significance level (alpha: probability that test statistic is in critical region when null is true, so it"s a mistake. If question asked is directional alpha is on one side. Critical value if not, alpha splits into two: value that separates critical region from values of test statistic that don"t reject the null hypothesis. P-value: know what the question is asking (directionality, remember, probabilities for z-scores are measured starting from the left, reject null if p-value <= alpha (significance level) Conclusions: fail to reject the null.