Formulas for Final Exam - Methods And Statistics Political Science | POL 221, Exams of Political Science

Download Formulas for Final Exam - Methods And Statistics Political Science | POL 221 and more Exams Political Science in PDF only on Docsity! Methods and Statistics in Political Science POL221 Last updated: October 18, 2007 Formulas for Final Exam Mean n X X   Standard deviation 1 )( 2    n XX sX Z score X X s XX Z   Standard error for interval/ratio or interval-like ordinal variable (when X is unknown) n s s X X  Standard error for interval/ratio or interval-like ordinal variable (when X is known) n X X    t score X X s XX t   Standard error of a sampling distribution of proportions (for a nominal variable) when uu QP , are known n QP uu PS  Standard error of a sampling distribution of proportions (for a nominal variable) when uu QP , are unknown n QP s ssPS  Confidence interval of a population mean (100% - α) CI of ))(( XX stX   Confidence interval of a population proportion 1 (100% - α) CI of ))(( spsu stPP  Sample size for the confidence interval of a population proportion (for a nominal/ordinal variable) 2 2))()(( Errorterm tQP n SS  Sample size for the confidence interval of a population mean (for an interval/ratio variable) 1 )()( 2 22  Errorterm st n X Single-sample means test Test statistic X X X s X t   Degrees of freedom 1ndf Large single-sample proportions test Test statistic s s P us P PP t    Sample size 5)])([( nPs 5)])(1[(  nPs Two-group difference of means test, independent groups Test statistic 2 21 21 XX XX s XX t     Standard error When group variances are equal 21 21 21 2 2 2 1 2 )1()1( 21 21 nn nn nn snsn s XX XX      When group variances are not equal 11 2 2 1 2 21 )(21      n s n s s XX XX separate Degrees of freedom When group variances are equal 2