Help with STATS

Jacy asks you what the purpose of a confidence interval is. Choose the answer that best describes the purpose. {:2- The purpose is to measure how well the sample represents the population. {:1- The purpose is to to determine where we believe the true mean or proportion {etc} lies, with a certain degree of confidence. CI- The purpose of the confidence interval is to tell the accuracy and sets the width of the interval. CI- The purpose is to find an interval that is useful and accurate to our data. 1) What property does Joni want to be true to make sure 0 is an unbiased estimator of 0? OE(0) - 0 =0 OE (0) -0=0 OE(0) - 0 0 O None of them OE( 0) - 070 2) How should Aaliyah define S to make sure that it is an unbiased estimator of o'? 1 O (; - ) O n n - 1 i 1 O None of them O n - E( xi - 2)2 i O L E ( x - 1)