To determine p, the proportion of time that an airline operator is busy answering customers, a supervisor observes the operator at times selected randomly and independently from other observed times. Let Xi = 1 if the ith time the operator is observed, he is busy; let Xi = 0 otherwise. For large values of n, if (1/n)/n i=1 Xis are taken as estimates of p, for what values of n is the error of estimation at most 0.05 with probability 0.96?

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