Unit Two Study GuideThis guide is intended to help guide you to the information that is likely to appear on the exam. While all information on the exam will be covered here, not all information covered here will make it to the exam. If you can comprehensively answer these questions you will find yourself well prepared for the exam.Chapter Five: Identifying Good MeasurementIn addition to the vocabulary presented in Chapter Five (bold terms), students should be able to comprehensively answer the following:1. What is operationalization and why do we want to operationalize variables?Give two examples of variables and their operational definitions. (Pgs. 114-115)-Operationalization is the process of turning a concept of interest into a measured or manipulated variable; the operational definition of a variable represents a researcher’s specific decision about how to measure or manipulate conceptual variable-We want to operationalize variables because it helps us measure and/or manipulate a variable we’re interested in-Ex: Happiness (operationalized)= research participants asked to respond to 5 items about their life satisfaction using a 7-point scale ranging from “strongly disagree” to “strongly agree”-Ex: Intelligence (operationalized)= researchers operationalize intelligence by creating graded intelligence tests that measure a variety of skills like vocabulary, reasoning, and pattern detection.2. What are the three most common types of measurement? What are the benefits and drawbacks of each? (Pgs. 116-118)-Self-Report: operationalizes a variable by recording people’s answers to verbal questions about themselves in a questionnaire or interview; Pros: easy to administer, good for quick measure of relationship between variables, Cons: wording of questionscould bias responses-Observational: operationalizes a variable by recording observable behaviors or physical traces of behaviors; Pros: directly measures behavior, gives researcher an “insider” view, open-ended, flexible, Cons: time-consuming, not generalizable, participants may not act in their true nature-Physiological: operationalizes a variable by recording biological data such as brain activity, hormone levels, or heart rate, and usually requires the use of equipment to amplify, record, and analyze biological activity; Pros: ? Cons: ?3. Be able to distinguish the two types of measurement scales (categorical & quantitative). Give two examples each. (Pg. 118)-Variables can be classified as either categorical or quantitative-Categorical: group variables into categories; Ex: sex, species-Quantitative: variables coded with meaningful numbers; Ex: height, weight4. What are three distinct types of quantitative variables? Give 2 examples of each. (Pgs. 118-119)-For some statistical purposes, researchers may need to further classify a quantitative variable using 3 distinct scales:1)Ordinal scale: applies when the numerals of a quantitative variable represent a rank order; Ex: a travel website might classify a set of resorts as two, three, or four stars—we know that 4-star resorts are better than 3- or 2-star resorts, but we do not know how much better they are; Ex: a professor might use the order in which exams are turned in to operationalize how fast students completed the exam—This is ordinal data because the fastest exams are on the bottom of the pile (ranked 1), but does not quantify how much faster each exam was turned in compared to the others.2) Interval scale: applies to the numerals of a quantitative variable that meet 2 conditions: 1) the numerals represent equal intervals (distances) between levels, and 2) there is no “true zero” (a score of 0 does not mean “nothing”); Ex: IQ tests—the distance between a score of 100 and 105 represents the same distance between a score of 110 and 115. However, a score of 0 does not mean a person has “no intelligence”; Ex: Temperature in degrees Celsius—intervals b/w levels are equal, but a temperature of 0 does not mean “no temperature”; Ex: questionnaire scales which utilize a 1 to 7 scale; ***Because interval scales do not have atrue zero, they cannot allow us to say things like “twice as hot” or “three times happier”***3) Ratio scale: applies when the numerals of a quantitative variable have equal intervals and a “true zero” (the value of zero truly means “nothing”); Ex: weight and income—someone, for instance, could truly be lifting “zero weight”, or have “no income”; ***Because ratio scales do have a true zero, we are able to say things like “John ran twice as fast as Michael”5. What are the three types of reliability discussed in class? Give an appropriate situation for utilizing each type of reliability? (i.e. when would you use each?) (Pgs. 119-121)-The reliability of a measure is just what the word suggests: whether or not you can rely on a particular score. If your measurement is reliable, you get a consistent pattern of scores every time. Reliability can be assessed in 3 ways:1) Test-retest reliability: the researcher gets consistent results every time he or she uses the measure; Ex: Scores generated by people who take an IQ test today shouldbe consistent when they take it 1 month later; the scores may be higher or lower the second time, but the pattern should remain consistent (those who scored highest on test 1 should also score highest on test 2); Test-retest reliability is relevant no matter the mode of operationalization; it is primarily relevant when researchers are measuring constructs they expect to be stableover time (intelligence)2) Interrater reliability: when two or more observers come up with the same (or very similar) findings; when consistent results are obtained no matter who measures or observes; most relevant for observational measures; Ex: 2 observers are assigned to record how many times a child smiles in 1 hour on a daycare playground—if they both record the same number of smiles, we can say that there is interrater reliability3) Internal reliability: when a study participant gives a consistent pattern ofanswers, no matter how the researcher has phrased the question; Ex: suppose a sample of people take, for example, Diener’s five-item well-being scale—the questions are worded differently, but each item is intended to be a measure of the same construct.
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