FORMULA SHEET DESCRIPTIVE STATISTICS Population N Ex; i=1 ? = N N ?(x ;- p)2 N 02 = i=1 ?=Vo? Sample n M= n * 8 = i=1 s2 = i=1 E (x-x)2 n n-1 S= Vs- N i x x i i 1 w N 3 i i=1 Weighted average Coefficient of variation Correlation coefficient 5x ×100% CV = X cov (xy ) r = SxSy PROBABILITY P(A') = 1 - P(A) P(A U B) = P(A) + P(B) - P(An B) Complement Addition Rule Conditional Probability P(A|B) = P(A n B) P(B) Multiplication Rule P(An B)= P(A).P(B|A) = P(B).P(A|B) Special Case: If A and B are INDEPENDENT then P(An B) = P(A).P(B) Total (or Marginal) probability P(A) = P(An B1) + P(A n B2) + P(An B3) + ... where B1, B2, B3 ... are mutually exclusive and collectively exhaustive DISCRETE PROBABILITY DISTRIBUTIONS E(x) = p = _ X; P (X;) N N i=1 o2 = > (x,-u1)2P(x) i 1 Binomial Formula P(X=x) = "CpX "-x BINOMIAL DISTRIBUTION where "C = n = n! x x!(n-x)!
mean u = np standard deviation o = vnpq