Hockenbury Discovering Psychology 5th txtbk

Descriptive Research Methods25One potential problem with surveys and questionnaires is that people do not alwaysanswer honestly. Participants may misrepresent their personal characteristics or lie intheir responses. These problems can be addressed in a well-designed survey. One strategyis to rephrase and ask the same basic question at different points in the survey orduring the interview. The researchers can then compare the responses to make sure thatthe participant is responding honestly and consistently.Correlational StudiesLooking at Relationships and Making PredictionsKey Theme• Correlational studies show how strongly two factors are related.Key Questions• What is a correlation coefficient?• What is the difference between a positive correlation and a negativecorrelation?• Why can’t correlational studies be used to demonstrate cause-and-effectrelationships?Along with answering the who, what, where, and when questions, the data gatheredby descriptive research techniques can be analyzed to show how various factors arerelated. A correlational study examines how strongly two variables are related to,or associated with, each other. Correlations can be used to analyze the data gatheredby any type of descriptive method.To illustrate, let’s look at a correlational study conducted by psychologistsCraig Anderson and Karen Dill (2000). Anderson and Dill were interested in howmuch time young people spent playing video games. They surveyed more than200 students taking introductory psychology classes at a large Midwestern university.Figure 1.3 shows some of the survey results. The students also completedsome personality tests and a questionnaire on past delinquent behavior. Finally,each student’s cumulative grade point average was obtained. Once the data wascollected, Anderson and Dill used a statistical procedure to calculate a figurecalled a correlation coefficient.A correlation coefficient is a numerical indicator of the strength of the relationshipbetween two factors. A correlation coefficient always falls in the range from1.00 to 1.00. The correlation coefficient has two parts—the number and thesign. The number indicates the strength of the relationship, and the sign indicatesthe direction of the relationship between the two variables.More specifically, the closer a correlation coefficient is to 1.00, whether it is positiveor negative, the stronger the correlation or association is between the two factors.Hence, a correlation coefficient of .90 or .90 represents a very strong association,meaning that the two factors almost always occur together. A correlationcoefficient of .10 or .10 represents a very weak correlation, meaning thatthe two factors seldom occur together. (Correlation coefficients are discussed ingreater detail in the Statistics Appendix at the back of this book.)Notice that correlation coefficients do not function like the algebraic numberline. A correlation of .80 represents a stronger relationship than does a correlationof .10. The plus or minus sign in a correlation coefficient simply tells you thedirection of the relationship between the two variables.A positive correlation is one in which the two factors vary in the same direction.That is, the two factors increase or decrease together. For example, Anderson andDill found that there was a positive correlation of .22 between the amount of timespent playing violent video games and aggressive personality characteristics. That is,surveyA questionnaire or interview designed to investigatethe opinions, behaviors, or characteristicsof a particular group.sampleA selected segment of the population usedto represent the group that is being studied.representative sampleA selected segment that very closelyparallels the larger population being studiedon relevant characteristics.random selectionProcess in which subjects are selected randomlyfrom a larger group such that everygroup member has an equal chance of beingincluded in the study.correlational studyA research strategy that allows the precisecalculation of how strongly related two factorsare to each other.correlation coefficientA numerical indication of the magnitudeand direction of the relationship (the correlation)between two variables.positive correlationA finding that two factors vary systematicallyin the same direction, increasing ordecreasing together.Figure 1.3 Time Spent Playing VideoGames Anderson and Dill’s (2000) surveyof 227 college students revealed that theamount of time participants spent playingvideo games decreased as they attainedhigher education. Notice that even at thecollege level, students reported playingvideo games for more than two hours perweek on the average.Average hours per week ofvideo game playing65432105.5Junior high school3.7Early high school2.7Late high schoolEducational stage2.1College