QBM公式总结.doc

统计学常用公式总结（上）SUMMARY OF FORMULAS (Chapter 4)总体均值Population mean =样本均值Sample mean 总体变量Population variance 样本变量Sample variance 标准差Population standard deviation 标准差Sample standard deviation Population coefficient of variance Sample coefficient of variance Approximate sample standard deviation Q123 Location of a percentile First (lower) decile = 10th percentile first(lower) quartile =25th percentile second(middle) quartile =median(50th percentile) third(upper) quartile =75th percentile Ninth(upper) decile =90th percentile SAMMARY OF FORMULAS (Chapter 5)= if A and B are mutually exclusive if A and B are independent If A and B are independent, then and SUMMARY OF FORMULAS (Chapter 7)Expected value (mean) Variance Standard deviation Laws of expected value: Laws of variance: Requirements for a discrete Bivariate distribution: for all pairs of values Laws of expected value and variance of the sum of two variables: Counting rule Binomial probability distribution for Binomial table: Mean and variance of binomial random variables: Probability distribution of Poisson random variables for Using the Poisson table to find the Poisson probability Using the Poisson table to find the Poisson probability SUMMARY OF FORMULAS (Chapter 8)Uniform distribution where Normal distribution Standardised normal random variable Mean Variance Normal approximation to the binomial distribution Exponential: Probability Mean Variance SUMMARY OF FORMULAS (Chapter 10)Sampling distribution of the sample mean Variance of the sample mean Standard error of the sample mean Standardising the sample mean Expected value of the sample proportion Variance of the sample proportion Standard error of the sample proportion Standardising the sample proportion SUMMARY OF FORMULAS (Chapter 11)Summary of interval estimators of and Parameter Confidence interval estimator Required conditions is known; is normally distributed or is unknown and estimated by , is normally distributed is unknown and estimated by , is normally distributed and and Summary of sample sizes for estimating and Parameter Sample size or or Parameter Test statistic Requi