PSY201H1 Lecture Notes - Lecture 6: Variance, Random Assignment, Statistical Hypothesis Testing
26 Oct 2016
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Lecture 6 (october 25, 2016): hypothesis testing, continued. Test review: there is a 6-point difference between two sample means. If the two samples have the same variance, then which of the following values for the variance would make the mean difference easiest to see in a graph showing the two distributions. Having a smaller amount of variance makes it easier to see the same mean difference between two distributions. It doesn"t matter, since both have the exact same variance. As so as you see how much, a hypothesis test cannot answer the question. Hypothesis test can only answer a yes or no question. Practice: directional (one-tailed) t test: we hypothesize that eating chocolate leads to decreased cortisol levels. It is known that normal cortisol levels during stress are normally distributed with = The average cortisol level for our sample of 9 chocolate eating participants is m = 19 with s = 2. 5.
