# Basic practice of statistics.docx - BASIC PRACTICE OF...

• 5

This preview shows page 1 - 3 out of 5 pages.

BASIC PRACTICE OF STATISTICS1. MEASURES OF CENTRAL LOCATON A.Mean i.Population mean = mu1.Sum of all observations divided by how many individuals that there are in the population 2.Unknown parameterii.Sample Mean = X1.X = Ex /n2.StatisticB.Mediani.Population median = n ii.Sample median = M
2. MEASURES OF SPREADA.Constant… when all the values of a characteristic are the samei.Both mean and median are the constant valueii.No spread in the dataB.Variable… when all the values are not the samei.Amount of spread (variability) around the central valueC.Range = maximum value – minimum valuei.Overall variation not the variation around the central valueii.Heavily influenced by outliersD.Standard deviationi.Measure of variability around the meanii.Deviation is the amount that an observation differs from the mean: x-Xiii.Population standard deviation = sigmaiv.Sample standard deviation = S1.Calculate the sample mean X2.Compute the n deviations from the mean: x-Xa.Will always equal 0 3.