# Psyc 3000 test 2!

 IV Examples Mood when manipulated by researcherMovie when selected by researcher. True IV: Quasi-IV: Many quasi-IVs are.... Researcher sets or manipulates IV Researcher observes BUT DOES NOT MANIPULATE level participant variables Quasi-IV Researcher observes BUT DOES NOT MANIPULATE level Example of Quasi-IV Mood when participant shows up for studyMovie when selected by participantSex of participant Cell or Condition Ex: A combination of IV levels Study of sex differences among drivers in two countries (USA & Greece) Confounding variable Other names = What do they do? AKA confound, covariate, or 3rd variableAffects DV. but is not an IVCan bias study, lead to wrong conclusionUltimately has affect on IV (IV STIMULUS --> DV RESPONSE --> Confounding variable --> IV STIMULUS) Examples of covariates Whats the order Date -> ______ -> Data, statistical analysis, Information What are the two types of statistics? Descriptive StatisticsInferential Statistics Descriptive Statistics: Goal? Problems? Best way to describe a variable is? Summarize/Describe the data from your study (the sample) Goal:Try to summarize data with two numbers without sacrificing crucial data: Average = Signal Variability = Noise Problems: Information lossAssumptions Best way to describe a variable is  by its type (nominal, ordinal, etc) and distribution Inferential Statistics: Are used to make predictions/inferences about the population based on the sample Average: Common averages: Single value most typical of all data Mean = Meadian = Mode = Most freq value Mode = Works best for what distribution? Used to describe? Okay for what types of data? -Most freq value-Works best for unimodal distribution-Used to describe average of nominal variable-Okay for what types of data: (Ordinal Interval or Ratio) Median = APA format =? Apa = MdnDivide Data in half ( 125 ) Mean = Used to describe which data? Mean = Best guess average of interval or ratio variables, but only if distribution is unimodal and symmetric (not skewed) IF distribution is unimodal and symmetric Mode = Mdn = M If distribution is unimodal with positive skew: Mode < Mdn < M if unimodal Would you report Mean, Median, or Mode? Eye Color Test Score (0-50)- Normal Distribution Test score (0-50)- Highly Skewed Distribution Temperature-- Normal Distribution SIze of dog (small, medium, large) Exam Grades (A, B, C, D, F) INcome under (10k, 10-20k, 20-30 etc) Eye ColorTest Score (0-50)- Normal DistributionTest score (0-50)- Highly Skewed DistributionTemperature-- Normal DistributionSIze of dog (small, medium, large)Exam Grades (A, B, C, D, F)INcome under (10k, 10-20k, 20-30 etc) What is mean, median, mode of 1 1 4 Mean =Median=Mode = 1 Which would u use? Mean median mode Small Small Small Small Medium Medium Medium Large Large Mode???? Does average completely describe the data? Solution? No, because two distributions can have same average but look very different. Need at least one other descriptive statistic. Variation Aka: Dispersion/Spread *Single most typical difference from average *Need to describe how much scores differ from average (ho wmuch noise is present) IQR Extends from? Often used for? Variabilities:                 How to measure them? Range: IQR: Interquartile Range- Middle half of scores25th - 75th percentileOrdinal Data Variabilities:Range = Largest datum - smallest datumIQR= Q3-Q1where Q3 is the median of the upper half and Q1 is the median of the lower half of data.  Q2 is the median of all data Variance = Squared Standard Deviation Standard Deviation = Know formula Mean deviation from M, ignoring sign (sort of) Standard Deviation Different Mean = Same Mean = Different Mean = Different Mean = Same SDSame Mean = Different SDDifferent Mean = Different SD Descriptive Statistics to report in Method Section/Participant subsection Sex: # of M & # of FAge: Min, Max, and either M and SD (of symmetric) or Mdn and IQR range (of skewed) Other key demographics such as ethnicity if important Descriptive Statistics of DV to report in... Results SectionIf DV is nominal or ordinal with few levels:Mode for each cellIf DV is ordinal, or interval/ratio and skewed: n, Mdn, and IQR rang for each cell If DV is interval/ratio and symmetric: n, M, and SD for each cell Descriptives calculate: M, SD, Min, and Max AuthorAnonymous ID206029 Card SetPsyc 3000 test 2! DescriptionPsyc 3000 Updated2013-03-09T22:18:27Z Show Answers