Suppose that the compression strength observations on the fourth type of box in Example 10.1 had been 655.1, 748.7, 662.4, 679.0, 706.9, and 640.0 (obtained by adding 120 to each previous x4j ). Assuming no change in the remaining observations, carry out an F test with .05.

Statistical Inference: provides methods for drawing conclusions about a population from the sample data. There are two ways to do this: Confidence intervals: used to estimate the value of a population parameter using sample statistics Test of Significance: used for assessing evidence for a claim about the population To set up Have to have an SRS from the population, no bias The variable has to have an exactly normal distribution in the population We don’t know population mean , but we know the population standard deviation Confidence Interval What statistic can be used to estimate the population parameter o We can use x-bar To do a confidence interval, it is similar to the 68-95-99.7