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HW #1The Scientific Method:Uses intuition or authority to find questionsAsks empirical questionsQuestions that can be testedNumber (quantitative) informationData drivenEvidence used to support conclusionsObjectiveFindings can be verifiedA Loop:Theory DeductionDeduction HypothesisHypothesis InductionInduction TheoryRecall:Deductive Reasoning: general specificInductive Reasoning: specific data general theoryGoals of Psychological Research:Describe BehaviorPredict BehaviorExplain Behavior (determine its causes)Control BehaviorWhat is Statistics?Statistics refer to a set of mathematical procedure for organizing, summarizing and interpreting informationPurpose of Statistics:Communicate the results to others: stats are used to organized and summarize the info from the research studyAnswer general research questionsTwo Branches of Statistics:1) Descriptive Stats: used to organize, summarize and communicated dataThe goal is to reduce a large amount of info into a smaller set of “bullet points”Ex.) the average exam score was 78, and scores ranged between 55 and 992) Inferential Stats: use samples to draw conclusion about a populationDid results come from fluke or random chance?Population:A pop is an entire set of individuals that possess some attribute that we are interested in studyingIdeally, we want to used the results of our study to describe this larger groupHowever, it is not usually feasible to collect data from the entire populationSample:A sample is a subset of individuals selected from a populationWe seek to a have representative sample.Random samples tend to be the best representative of the populationParameters and Statistics:Parameters: Numerical values summarizing population dataStatistics: Numerical values summarizing sample dataPopulation means parameter, Sample means statisticsVariables: any observation of a physical, attitudinal or behavioral characteristic that can take on different values.Can be classified as several typesDiscrete or Continuous (Nominal, ordinal, interval, ratio)Independent, Dependent, CofoundinalDiscrete Variable: Separate, invisible categories “Categorical”Continuous Variable: divisible into an infinite number of fractional parts “Quantitative”Measurement Scales:Nominal Scales (Discrete):set of categories that have different namesNo quantitative information at all (Ex. gender)Ordinal Scale (Discrete):Set of categories that are organized in a ordered sequence (Ex. race order 1st, 2nd, 3rd …)Do not know how long in between each intervalInterval Scales (Continuous):Ordered categories that are all intervals of exactly the same sizeHas an arbitrary zero point (Ex. Fahrenheit)Ratio Scale (Continuous):An interval scale with an absolute zero point (Ex. minutes, miles, heart rate)Likert Scales:Likert scales are very common in psychologyTend to treat them as interval scalesHow much do you like _____?1 Strongly Disagree2 Disagree3 Slightly Disagree4 Neutral5 Slightly Agree6 Agree7 Strongly AgreeIndependent Variable (IV):AKA Exploratory VariableCan be manipulated or observedDependent Variable (DV):AKA Response VariableOutcomeConfounding Variable:AKA Lurking VariableSystematically varies with IV so that we cannot determine which variable is influencing the DVHypothesis Testing and Operation Definitions:Define a variable in terms of operations used to measure or manipulate itDefineLoveAggressionDepressionHappinessHelpingBest to use multiple operational definitions when measuring a constantCreating and Assessing Variables:Reliability: consistent results? Doesn’t have to be right, but is still reliable!Validity: extent the test measures what it is supposed to measure.Types of Research Designs:Experiments:random assignment of participantsNon Experiment/Quasi Experiments:random assignment not possibleCorrelation Research:No manipulation of IVExamine how two variables vary togetherNo causationBetween Subjects Designs:Each level of the IV has one group:Or each participant is in one level of the IVBenefits:Eliminates many possible confoundsProblems:Requires lots of participantsWithin Subjects Design:Ex. studying which genre of music you listen to before a test and how it effects youEach participant gets each level of the IVBenefits (needs less participants)ProblemsOrder effects: listening to one type of music may influence your score for the next roundsTesting effects: getting used to the testFatigue effects: getting tired of itHW #2 Due 9/9/13Descriptive Stats:Organize, summarize, and communicate numerical infoFrequency distributions are a type of descriptive statsFrequency Distributions:Our data consists of several raw scoresA frequency distribution describes the pattern of a set of numbersDisplays counts or proportion for each possible variableFrequency table shows how many raw scores were at each valueValues listed in 1 columnNumber of individuals with scores at that value in second column.Structured as:Table: scores ordered high to lowList scores low to high, add up each individual score, add percentage columnGraph: scores ordered low to highTwo elements:Categories or original measurement scaleFrequency or number of individual categoriesGrouped Frequency Tables:Appropriate for continuous dataRepresent ranges of values instead of each possible valueRound down highest and lowest values and find the rangeAdd one to the rangeDetermine the interval, easily understood whole numberBottom range should be a multiple of the intervalEx. High: 100Low: 46 round down to 40Histograms:X-Axis = variableY-Axis = frequencyCenter bars on value whose frequency is being representedUse middle of interval for grouped frequenciesFrequency Polygon:Constructed like a histogram except with data points and linesCreate hypothetical zero points for each end of the data rangeInstead of bars (histograms), dots to connect lines on a graphHW #3Shapes of Frequency Distributions:Most common is the Normal DistributionBell-shapedSymmetricUnimodalMany phenomena are normally distributedHeightIQSAT or ACT ScoresSkewness: *Paper Notes*Asymmetrical distributionSkewed distributions have scores piled up at one end and taper off at the otherThe section where the scores taper off is called the tail of the distributionPositively Skewed: tail on the right-hand sideOLI – “Skewed right distribution”Negatively Skewed: tail on the left-hand sideOLI “Skewed left distribution”Common Types of Graphs:Scatterplots:Depicts relation between two continuous (scale)

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