Sampling StrategiesSample a PopulationWant to be able to generalize conclusions, so the sample should represent the populationControl person and situation variablesPlanned uniformityYou can only generalize something to one groupSystematic variationRandomizationInteraction effect: when two variable combine to produce an effect, they have to be considered in combination to predict an outcomeInteraction: the relationship between one variable and another variable depends on a third variable.. means “it depends”A classic interaction effect will look like an “X”“Moderator Variable”: another way of saying there is an interaction present; its another way of describing an interactionReliability and CorrelationReliability: ability of a measure to yield “consistent” resultsConsistency doesn’t mean accurateEx: Playing darts: you consistently hit the board with the dart, but you fail to hit the bulls eyeThus, you’re consistent but not accurateConsistency is measured by correlationIf the measure is reliable the correlation will be high, with a low reliability the measure or correlation will be zeroReliability is measured form 0- +1 (you should never have a negative number)This consistency typically calculating the correspondence between 2 measurementsAll involve some form of correlation coefficientMethods of estimating reliabilityTest-retestGive a measure once, then give it a second time in the futureCalculate the correlation between the 2Internal consistency/ split-halfInstead of giving the measure twice, correlate the two halves of the measureTells you that the different items are consistency measuring the same thingScorerThe two lists of numbers being correlated are listed proved by different score*Construct: things that help describe and explain the things we observeEx: introversion vs. extroversionUsed to help explain the differences in peopleEx: IntelligenceIQ tests used to try and measureReliability Studies: SamplingMake certain the sample is representative of the populationLecture 3 Outline of Last Lecture I. Characteristics of a theory Outline of Current Lecture II. Sampling Strategies III. Interaction Effect IV. Reliability and Correlationa. Methods of estimating reliabilityi. Test-retestii. Internal consistency/split-halfCurrent Lecture Sampling Strategies - Sample a Populationo Want to be able to generalize conclusions, so the sample should represent the population- Control person and situation variableso Planned uniformity You can only generalize something to one groupo Systematic variationo Randomization Interaction effect: when two variable combine to produce an effect, they have to be considered in combination to predict an outcome- Interaction: the relationship between one variable and another variable depends on a third variable.. means “it depends” - A classic interaction effect will look like an “X”- “Moderator Variable”: another way of saying there is an interaction present; its another way of describing an interactionReliability and Correlation- Reliability: ability of a measure to yield “consistent” resultso Consistency doesn’t mean accurate  Ex: Playing darts: you consistently hit the board with the dart, but you fail to hit the bulls eye Thus, you’re consistent but not accurate PSYC 330 1st Edition Consistency is measured by correlation If the measure is reliable the correlation will be high, with a low reliability the measure or correlation will be zero Reliability is measured form 0- +1 (you should never have a negative number) This consistency typically calculating the correspondence between 2 measurements  All involve some form of correlation coefficient Methods of estimating reliability Test-retest - Give a measure once, then give it a second time in the future- Calculate the correlation between the 2 Internal consistency/ split-half- Instead of giving the measure twice, correlate the two halves of the measure - Tells you that the different items are consistency measuring the same thing  Scorer- The two lists of numbers being correlated are listed proved by different score *Construct: things that help describe and explain the things we observe - Ex: introversion vs. extroversiono Used to help explain the differences in people- Ex: Intelligenceo IQ tests used to try and measure  Reliability Studies: Sampling- Make certain the sample is representative of the populationThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a