商务统计公式总结.doc

。l Sample meanl Q1 at (n+1)/4l Q2 at (n+1)/2 (the median position)l Q3 at 3(n+1)/4l Interquartile range = Q3 Q1l Sample variance l Sample standard deviation l Coefficient of Variation l Z Score l Population mean l Population variance l Population standard deviation l Chebyshev Rule: at least (1 - 1/k2) x 100% of the values will fall within kl P(A or B) = P(A) + P(B) - P(A and B)ll Two events are independent if and only if: ll (If A and B are independent)l select X objects from n objects: (number of different ways)l select and arrange: l Expected Value ( mean) (discrete distribution) l Variance of a discrete random variable l Standard Deviation of a discrete random variable (X successes in n trials) Binomial Distribution Mean Variance Standard Deviation Discrete ProbabilityDistributions (l=expected number of events; e = 2.71828.) Poisson Distribution Mean Variance Standard Deviation Standardized Normal Distribution translation of the Mean (is normal if population is normal or n 30) Sampling Distributionsof the Proportion(normal distribution if ) is Knownfor the Population Mean, Confidence Intervals is UnknownConfidence Intervals forthe Population Proportion, for meanDetermining Sample Size for proportion can be estimated with a pilot sample (or conservatively u