# Values ordinal when to use modemed nominal discrete

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values, ordinalWhen to use mode>med:Nominal, discrete var, huge rangeExample:Modal: 5Median: 115+1/2 = 58 = 5Range: 12-1= 11Mean: 115/27 = 4.26SD: sqrt(205.25/27-1) = 2.812.7 Measure of SpreadSummary stats: dist using a single numberVariability: provides measure of degree to which scoresspread out/clustered togetherVariation ratio: categorical, gives proportion of cases not in modal category (larger VR, more diverse)VR = 1 – (fmodal/n)Range: ignores info about dist, affected by outliersVariance: avg of squared deviations of each variable from mean valueSD: how spread your data is from the mean (the bigger,the more concentrated, the smaller SD)Deviation: distance and direction from meanSx= sqrt(sum of all (x-xbar)^2 / n – 1)3.1-5.1 Probability & Probability Distprobability:proportion of times the outcome would occur out of all possible timesRandom: ind outcomes are uncertain, nonetheless a regular dist of outcomesSamp space: list of all possible outcomesSamp pt: just one of possible outcomes (Sample space is made up of samp pts)Rules of Probability: 1.P(A) is btwn 0 and 12.S is sample space in probab model, P(S) = 13.Add Rule: probab of any several diff mutually exclusive outcomes is equal to the sum of their separate probabilities4.Multiplication Rule: probab of a combo of independent outcomes is equal to the product of their separate probabilitiesAdd Rule: P(A or B) = P(A) + P(B)Mutually Exclusive: if both possibilities can’t happen together (test if P(A and B) = 0, it is ME)If not: P(A or B) = P(A) + P(B) – P(A and B)Mult Rule: dependent or independentIndependent: knowledge of one event doesn’t help predict probability of second event occurringTo test if ind, P(A) = P(A|B), P(B) = P(B|A), P(A and B) = P(A)*P(B)If dependent: P(A and B) = P(A)*P(B|A)Conditional prob: prob of one event occurring (B)given that another event has occurred (A), P(B|A)ConventialTies0-23-56 or moretotalStrong2513644Weak16131645Total41262289P(Strong) = 44/89=0.49P(6 or more) = 22/89 = 0.25P(0-2 or 3-5) = 26+41/89 = 0.75P(weak or 3-5) = P(weak)+P(3-5)-P(weak and 3-5)45/89+26/89-(45/89*26/89) = 0.65P(6 or more|strong) = 6/44 = 0.14P(weak and 0-2) = 16/89 = 0.18Are convential ties & criminal acts ind or dep?
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