POLI 30 Lecture Notes - Lecture 14: Confidence Interval, Statistical Inference, Statistic
Document Summary
Say something about a population parameter using a sample statistic. Statistical inference: saying something about the unknown using the data you have at hand. Distinguishing between random noise and real patterns. These questions are partly answered with confidence intervals. We are 95% confident that the true value is in some range. If the probability is small, then reject the possibility that the true value is theta. How diverse is the population, how big is the sample, what are you. The more diverse the population, the less accurate sample statistic. The more homogeneous the population, the more accurate the sample statistic. No variance in income: no matter who you sample or how many, your sample average will always be on population average. Who you sample has a big impact on the sample average. When sampling from a population with low variability, our sample mean is very likely to be close to the true population parameter.
