STAT1008 Chapter Notes - Chapter 4: Null Hypothesis, Statistic, Alternative Hypothesis
Document Summary
A statistical test uses data from a sample to assess a claim about a population. Statistical tests are framed formally in terms of two competing hypotheses : Null hypotheses (h0): claim that there is no effect or difference. Alternative hypothesis (ha): claim for which we seek evidence. The alternative hypothesis is established by observing evidence (data) that contradicts the null hypothesis and supports the alternative hypothesis. Ha usually includes >,< or ( depends of the question) When results as extreme as the observed sample statistic are unlikely to occur by random chance alone ( assuming the null hypothesis is true), we say the sample results are statistically signi cant. If our sample is statistically signi cant, we have convincing evidence against h0, in favor of ha. If our sample is not statistically signi cant, our test is inconclusive. Statistical signi cance is a dif cult concept, but also one of the most fundamental concepts.
