ADM 2304 Lecture Notes - Lecture 6: Normal Distribution, Null Hypothesis, Covariate
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> proportions are not independent so we cannot ignore the covariance factor variance of the sample difference however now as a covariate term: e. g, in a sample of 1,000 respondents 39% indicated support for the. Conservatives and 34% indicated support for the liberals. Can we state that there is a real difference between the two at a signi cance level of 5%? ph. > therefore we do not reject the null hypothesis, 1. 85 is less than 1. 96 (the 95% shit). There is insuf cient evidence to suggest that there is a real difference between the liberal and conservative support. > we can assume that the distribution of the difference between the two sample means is normal. > if we don"t know the population sds and use instead the sample sds then we can use the t-distribution instead. > suppose we are interested in determining whether there is a statistical difference between the means of two populations.