POLS 2400 Chapter Notes - Chapter 7: Null Hypothesis, Sampling Distribution, Normal Distribution
13 Dec 2016
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Estimating means and proportions does not constitute the primary decision-making goal. Any departure from expected results is due to sampling error. Hypothesis includes a comparison between two groups. If the results are reasonable-> retain the hypothesis. Two samples have been drawn from equivalent populations. States that any observed difference is due to sampling error. Cannot reject the null hypothesis unless there is enough contradictory evidence. Generally want to reject the null hypothesis. Means are different-> accept the research hypothesis. Example-> find 100 means of 100 samples. A frequency distribution of a large number of differences between sample means that have been randomly drawn from a given sample. Approximates a normal curve whose mean is zero. If the actual mean difference between the populations of females and males is zero-> mean of the sample distribution of differences between samples means is also zero. Testing hypothesis with the distribution of differences between means.
