Second Midterm Formula Sheet - Introduction to Statistics | SOCY 201, Study notes of Statistics

Download Second Midterm Formula Sheet - Introduction to Statistics | SOCY 201 and more Study notes Statistics in PDF only on Docsity! a Formula Sheet for Second Midterm Exam number of observations = N proportion = £ percentage = L100) = =X, . . strides ib sample mean X = Wr population mean = mean of sampling distribution = wy a sample variance s? = population variance o?” Standard error of the mean o ¢. Estimated standard error of the mean ¢- === VN * N-1 Z scores: for an individual observation Zy = Ai-X ‘ Ss forasample mean Z,, = X-H ° o5ore. P-P. for a sample proportion Z, = ——+—"—_- é © YPU- PIN ¢ X- t-score for a sample mean te # o0rs Degrees of freedom for one sample mean =N — 1 Degrees of freedom for a test of a difference between 2 means = N, +N, -2 Confidence interval around a sample mean Confidence interval around a sample proportion LargeN ci. = XtZ-(o- ord.) Large N SmallN ci. = X+t-(c- ord.) : * Z- score for a difference between 2 means, large samples: X1- Xo -(t4, - a (@.-x2) = Hi- Xi tn) where Oy,3,) = fat FE, -¥1)°"? (¥,-¥2) ° N t- score for a difference between 2 means, gf 08 ~ ; small samples A ae fin \ a i € R t _ ,-*,)-G4 —-b,) “ ee or Reality r Your Decision ; obtained 3 7 oe we eali' ccept Nu Reject Nui Ns) tNoSy IN, +N, ‘ : ) Null is true Probability of Probability of N,+N,-2Y NN, correct decision: Type I error: l-a@ « A 4 . Null is false Probabitity of Probability of / . Type II error: correct decision: 4 ; 1-8 Me wen ff ac Fe adore OF correct decisca, pun te 5 fer Ween