Confidence Intervals - Introduction to Statistical Methods | STAT 301, Study notes of Data Analysis & Statistical Methods

Download Confidence Intervals - Introduction to Statistical Methods | STAT 301 and more Study notes Data Analysis & Statistical Methods in PDF only on Docsity! 21 September Confidence intervals for π P = Zcrit √ p(1−p)n Interpretation We are _% confident that the true proportion of _ is between (LB) and (UB). Other acceptable interpretations If we repeated this study 100 times, _(%) of the intervals would include π, the true population proportion for _. Note Any interpretation that implies π changes is WRONG! The population parameter is fixed – we just don’t know what it is. Bad interpretation There is a 95% chance that π is between 0.34 and 0.66. Using CI for π to find CI for a total If you know a CI for the proportion of a population within a characteristic of interest, you can find a CI for the total number of objects with the characteristic of interest in the population, as long as you know the total number of objects in the population overall. N = # of objects in population Np is estimate of total number of people with characteristic of interest CI for total # in population with characteristic is N(CI for π) Margin of error