STATS 10 Lecture Notes - Lecture 15: Null Hypothesis, Confidence Interval, Alternative Hypothesis
Document Summary
Earlier we calculated a 95% confidence interval for the true population proportion of ucla students who traveled outside the us. A 95% confidence interval of 26% to 44% means that: (0. 26, 0. 44) We are 95% confident that the true population proportion of ucla students who traveled abroad is between 26% and 44%. 95% of random samples of size n=100 will produce confidence intervals that contain the true population proportion. The true population proportion, p, may be outside the interval, but we would expect it to be somewhat close to p-hat. In our random sample of 100 students we found that 35 of them have at some point in their lives traveled outside the us, p-hat = 0. 35. It is difficult to decide how close is close enough, or how far is too far, and this decision should not be made subjectively. In statistics, when testing claims we use an objective method called hypothesis testing.
