MATH 10041 Lecture Notes - Lecture 26: Null Hypothesis
30 Mar 2019
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8. 4: comparing proportions from two populations: conduct a hypothesis test comparing two population proportions. In january 2014, the gallup organization reported that 45% of americans reported feeling pretty good about the amount of money they had to spend. Gallup reported that 49% of americans felt this way. In comparing two population proportions, the null hypothesis is h0: p1 = p2 the alternative hypothesis is one of these 3 possibilities: ha: p1 > p2, ha: p1 < p2. Changes to checking conditions: large samples, both sample sizes must be large enough. We use , the pooled sample proportion, where: 2. If we are not told explicitly that the sample was randomly drawn we may have to assume this condition is satisfied. Independent samples: the samples are independent of each other. Independent within samples: the observations within each sample must be independent of one another. Example: gallup poll on consumer confidence: researchers from the gallup poll interviewed two random samples.
