For testingH0: = 14 , H1: = 14 ,an =0 .05 level t-test is being considered. What sample size is necessary in order for the probability to be 0.1 of falsely failing to reject H0 when the true population mean diers from 14 by 0.5? From a preliminary sample we estimate to be 1.25.

Week 9: Distribution of Sample Means Statistical inference o Generalizing from a sample to a population, by using a statistic to estimate a parameter o Goal: to make a decision Different samples of size “n” will produce different values of the sample mean The population mean is fixed as long as the population does not change Sample distribution of x(with a line over it) is the distribution of all possible sample means calculated from all possible samples of size n o Also called the “population of all possible x- bars” Simple Random Sample (SRS) o Each sample of size n has the same chance of being chosen o To select SRS: