STAB22H3 Lecture 22: STAB22 – Lecture 22 – Continuation of Ch.16 and Intro of Ch. 17
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Stab22 lecture 22 continuation of ch. Half of that is 5% = 0. 0500. Table: z = -1. 64 or -1. 65 has 0. 0500 less. Z = 1. 64 or 1. 65 has 0. 0500 more (0. 9500 less) But different samples have different p-hat"s and give different confidence intervals. Another sample, with n= 1000, might have p-hat = 0. 89, giving 95% confidence interval for p of (0. 870,0. 910) Ex: a newsletter reported that 90% of adults drink milk. A survey in a certain region found that 652 of 750 randomly chosen adults (86. 93%) drink milk. One approach: confidence interval: square-root of (p-hat (1-p-hat)) / n = 0. 0123, 95% ci is 0. 845 to 0. 893, 99% ci is 0. 838 ~ 0. 901. Second approach: hypothesis testing: step 1: set up the null and the alternative hypotheses. Ha: p doesn"t equal to 0. 90: step 2: calculate the test statistics: H0: p = 0. 90 and p-hat = 652/750 = 0. 8693.
