Sharon Seidman Ph D CAS 301 Inquiry Methodology Sharon Seidman Ph D CAS 301 More on Data Collection Group Comparison Today s Agenda Article 2 presentations Review New information More on group comparisons More on data collection Planning upcoming activities Review 1 Sharon Seidman Ph D CAS 301 Inquiry Methodology Research Process Examine association between variables Develop hypothesis or question State specific testable prediction Collect data Variables Basis for research Individual elements of hypotheses predictions Must vary A variable Has levels Is a category Is a member of category Can change Cannot change Variable Definitions Concept Valid Face Predictive Concurrent Convergent Discriminant Operation Reliable Internal Test retest Inter rater Scale Ratio Interval Ordinal Nominal 2 Sharon Seidman Ph D CAS 301 Inquiry Methodology Variables Causality Types of variables Subject Situation Response Created vs pre existing variables Subject always pre existing Situation response may be Pre existing Created Goals of Research Description Prediction Causation Descriptive Statistics Inferential Statistics Describing a Group Norms Central Tendencies Mean Median Mode Individual Differences Variability Range Standard Deviation 3 Sharon Seidman Ph D CAS 301 Inquiry Methodology Kinds of Inferences Linear Relations Correlations Group Comparisons Experiments Comparison Between 2 Groups Based on Difference between group norms means Differences within groups standard deviation Odds that sample represents population degrees of freedom Produces probability of Type 1 Error Example Is the number of fights in classrooms with 20 children significantly greater than the number of fights in classrooms with 10 children Steps Sample classrooms in each group Count the fights in each room Compare groups to see if norm for 20 children classes is typical of 10 children classes 4 Sharon Seidman Ph D CAS 301 Inquiry Methodology Number of Classes Frequency of Fighting 20 Student Classes 4 5 6 7 8 9 10 Number of Fights Number of Classes Frequency of Fighting 10 Student Classes 2 3 4 5 6 7 8 Number of Fights Properties of a Normal Distribution 2 5 Area 2 2 2 5 13 6 34 1 34 1 13 6 2 2 Standard 3S 2S Deviation 1S Mean 1S 2S 3S 5 Sharon Seidman Ph D CAS 301 Inquiry Methodology 95 Comparing Groups 4 5 10 Children 6 7 8 9 10 20 Children T statistic Numerical representation of difference between groups t 18 3 75 p 05 Degrees of Freedom Probability of Type 1 Error Difference between means divided by standard deviation Degrees of freedom Related to sample size Possible variability in sample How much freedom is there to get a different score 6 Sharon Seidman Ph D CAS 301 Inquiry Methodology Probability Errors Research Decision Reality Null is True Accept Null Accept Hypothesis Type I Error Hypothesis is True Type II Error More on Group Comparisons Scales of Measurement Ratio Interval Ordinal Nominal Mean Median Mode Median Mode Mode 7 Sharon Seidman Ph D CAS 301 Inquiry Methodology Variables in Between Group Comparisons Grouping Variable Called independent or predictor Used as nominal measure Outcome Variable Called dependent or criterion Must Be interval ratio or Likert Accommodate math Defining Groups Created groups Independent variables Defined by experimenter Create experimental design Group creation strategies Random assignment Matched pairs Existing groups Predictor variables Defined by Subject variables Pre existing situation variables Create quasi experimental design Developmental Designs 8 Sharon Seidman Ph D CAS 301 Inquiry Methodology Developmental Designs Quasi experimental Examine change associated with age Attempt to differentiate development and experience 3 different designs Cross sectional Longitudinal Sequential Cross Sectional 1 2 Cohort Effects 3 4 Longitudinal Cross Sectional 1 1 2 2 3 3 4 4 9 Sharon Seidman Ph D CAS 301 Inquiry Methodology Longitudinal CrossSectional 1 1 1 2 2 2 3 3 4 4 Sequential 2 3 3 4 Intervention Designs Frequency Score Principle of Intervention Studies Before After Intervention 10 Sharon Seidman Ph D CAS 301 Inquiry Methodology Frequency Score Baseline Analysis Single Case Before After Intervention Frequency Score Pretest Posttest Analysis After Group Before Intervention Averages Frequency Score Posttest vs Control Analysis Test Group Control Group After Group Before Intervention Averages 11 Sharon Seidman Ph D CAS 301 Inquiry Methodology Types of Comparisons Two different groups of people Scores are independent of each other One measurement does not influence the other Independent group design One group of people before and after pretest vs post test Scores are related to each other One measurement does influence the next Repeated measures design Relations among Design Elements Existing vs created grouping variables Predictor vs independent variables Independent groups created by Random assignment Matched pairs Quasi experimental vs experimental Independent vs Repeated measures 2 different groups vs one group measured 2 times Longitudinal design repeated Sampling Assignment 12 Sharon Seidman Ph D CAS 301 Inquiry Methodology Sampling Identification of participants Strategies Random Entirely random Stratified random Cluster Haphazard Truly haphazard Random Quota Random Stratified Easy Haphazard Quota Assignment Creation of experimental groups Must be determined by experimenter Only applies to Independent Variables Strategies Random Haphazard Methods of Data Collection 13 Sharon Seidman Ph D CAS 301 Inquiry Methodology Data Collection Techniques Testing Observation Survey questionnaire Interview Content analysis Pre existing source archival data Observation Strategies Naturalistic vs Systematic Participant vs Concealed Issues Reactivity Reliability coding recording Sampling vs comprehensive Questionnaire Issues Measure ideas rather than behavior Ease data collection Evaluate sample characteristics Distribution Find target population Ensure adequate response rate Format Close vs open ended questions Influence of wording Reactivity Social desirability Order effects 14 Sharon Seidman Ph D CAS 301 Inquiry Methodology Content Analysis Analysis of thing rather than person Requires coding counting Interviews Same risks as Observations Surveys Advantages Detailed qualitative information Clinical interview flexibility What s Next 15 Sharon Seidman Ph D CAS 301 Inquiry Methodology Upcoming events Week 10 workday Identification of remaining articles 4 total for individuals 8 total for