STATS 250 Study Guide - Midterm Guide: Confidence Interval, Null Hypothesis, Statistical Parameter

• School: U of M
• Department: Statistics
• Course: STATS 250
• Professor: Brenda Gunderson

Document Summary

Never know true population parameter value, so take sample and use sample statistic to estimate parameter. Sample statistic may not match population parameter, and change everytime we take a sample. Researchers want to reject notion that chance alone can explain sample values that the researcher is fairly confident will cover true, unknown value of population parameter. Use a confidence interval to estimate value of a population parameter. Hypothesis testing: uses sample data to attempt to reject a hypothesis about population results. Achieving statistical significance is equivalent to to show that null value is not correct. rejecting idea that observed results are plausible if the null value is correct. Sampling distribution of statistic : distribution of all possible values of a statistic for repeated samples of same size from a population. (want to have approx. normal dist) No one can say how close observed sample proportion phat is to true population proportion p.