Research Methods Exam 2Chapter 5 Questions1. What is operationalization and why do we want to operationalize variables? Givetwo 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; any variable can be expressed in to wayso 1) Conceptual variable: researchers definition of the variable in question at an abstract levelo 2) Operational variable: researchers specific decision about how to measure or manipulate the conceptual variable - Operationalizing “happiness” Ed Diener reasoned that happiness might have variety of meaning so he made it “subjective well- being”; After definingit at a conceptual level, he chose to operationalize subjective well being by asking people to report on their own happiness with their life in a questionnaire format - Operationalizing “intelligence” researchers have agreed to define intelligence as a mental ability that involves capacity to “reason, plan, solve problems, think abstractly etc.”; Researchers have often operationalized it bycreating grading intelligence tests that measure a variety of skills- Operationalization are at one place where creativity comes into the research process as a variable can be operationalized in many ways 2. What are the three most common types of measurement? What are the benefitsand drawbacks of each? (Pgs. 116-118)- The three most common types of measurements are self- report, observational and physiological - Self-Report Measures: operationalizes a variable by recording peoples answers to verbal questions about themselves in a questionnaire or interview- Observational Measures: operationalizes a variable by recording observable behaviors or physical traces of behaviors - Physiological Measures: operationalizes a variable by recording biological data such as brain activity, hormone levels, or heart rate *****MISSING***** 3. Be able to distinguish the two types of measurement scales (categorical & quantitative). Give two examples each. (Pg. 118)- Categorical variables: are categories; (examples are sex, whose levels are male and female, or species, whose levels in a study might be chimpanzee, bonobo, macaque); a researcher might decide to assign numbers to the level of a categorical variable (for instance 1 is for chimps) but it is not quantitatively “higher or lower”- Quantitative variable: meaningful numbers; examples are height and weight; Diener’s scale of subjective well-being is quantitative because a score of 35 represents more happiness than a score of 7. IQ scores also4. What are three distinct types of quantitative variables? Give 2 examples of each. (Pgs. 118-119) - For statistical purposes, researchers need to further classify a quantitative variable as ordinal, interval or ratio- Ordinal scale: applies when the numerals of a quantitative variable representa rank ordero Ex. A travel website might classify a set of beach resorts as two, three or four stars- we know four is better than 3 but we do not know how much better they areo Ex. Professor might use order in which exams are turned in to operationalize how fast students completed the exam; the fast examsare at the bottom of pile ranked 1; however this variable has not quantified how much faster each exam was turned in, compared to others- Interval scale: measurement applies to the numerals of a quantitative variable that meet two conditions: 1) numerals represent equal intervals (distances) between levels and 2) there is no “true zero”o Ex. IQ Test distance between IQ scores of 100 and 105 represents the same as distance between 110 and 115; however a score of zero does not mean a person has no intelligence o Temperature in degrees Celsius intervals between levels are equal; however a temperature of 0 degrees does not mean that some entity has no temperatureo Ex. Questionnaire scales like Diener’s; do not have true zero, but assume distances between numbers are equivalent- Ratio Scale: measurement applies when the numerals of a quantitative variable have equal intervals and when the value of zero truly means “nothing”o Ex. Weight and income something that has no weight will have a true value of 0, and a value of 0 on income means that a person has literally no incomeo Brain activity value of zero will mean that some area of the brain has not increased in activity o We can say something like “Miguel ran twice as fast as Diego”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)- Test- Retest Reliability the researcher gets consistent results every time heor she uses the measure o Suppose a sample of people took an IQ test; when they take it 1 month later, the scores should be consistento Primarily relevant when researchers are measuring constructs (such as intelligence) that they expect to be stable over time (for instance subjective well being might fluctuate month to month)- Interpreter Reliability consistent results are obtained no matter who measures or observes o Two or more independent observers will come up with the same or very similar findingso More relevant for observable measures - Internal Reliability a study participant gives a consistent pattern of answers, no matter how the researcher has phrased the question6. What type of graph can be used to display information about reliability? (Pgs. 121-122)- Scatterplots 7. What type of coefficient can be used to evaluate reliability? How do we know if there is good reliability or weak reliability? What aspects of the coefficient should we pay attention to? (Pgs. 123-124)- The correlation coefficient r is a single number to indicate how close the dots on a scatterplot are to a line drawn through them- The r tell you the direction of the relationship and the strength of the relationship, both of which are used by psychologists in evaluating reliability evidence - The value of r can only fall between 1.0 and -1.0. - The numbers below the scatterplots are the correlation coefficient, or r8. What is Cronbach’s Alpha? How is it calculated (conceptually)? (Pg. 125)- Cronbach’s Alpha: correlation- based static to see if their measurement scales have internal reliability- First they collect data on the scale from a large sample of participants and then they compute all possible correlations
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