Download Week 6 Lecture: Sampling and Research Ethics in Behavioral Research Methods and more Study notes Psychology in PDF only on Docsity! 1 Psych 218 Introduction to Behavioral Research Methods Week 6: Lecture 11 Outline of Today’s Lecture • Last lecture we discussed – Establishing reliable measures for non- experimental research • Today we will discuss – Sampling – Research Ethics • Ethics associated with the use of human and animal subjects -- NIH Online Ethics class • General Research Ethics: Plagiarism & Scientific Misconduct Sampling • Why sample? We cannot usually measure the entire population of interest so we must rely on measuring a sample of the population • Goal of Sampling: to be able to generalize to everyone in the population of interest –sample must represent the population to insure external validity • Terms – population: any group with size greater than 1 – element: one member of a sample, e.g., person, family, city, country, etc. – strata: sub-group of sample which is homogeneous with respect to some variable - e.g., male/female Random Sampling Techniques • Simple random sample – need an entire list (or access) to all elements of population – draw sample using names in drum, random number table, etc. – given a big enough sample it will be representative each member of population has an equal chance of being sampled. • Systematic random sample (short cut) – still need list of every element – take every nth element, where n = pop size/sample size – pick first element randomly Stratified Sampling Techniques • Stratified (Homogeneous Subgroup) Sample – Proportional Stratified Sample • sample elements are in the same proportion as they occur in the population • allows inferences from sample strata to population strata • allows inferences from entire sample to entire population • problem: small strata may not give enough detail – Equal Stratified Sample • equal proportion of sample comes from each strata of population • different size of strata populations - insures stability of sample from smaller strata • each strata is equally representative of its target population • allows comparisons between strata - internally valid • EXAMPLE: views of political parties in America Other Sampling Techniques • Purposeful Sample – identify cluster of sample that is representative of entire population with respect to the variable of interest – randomly select from cluster • Incidental (convenience) Sample – sample from convenient or available population e.g., subject pool! most psychological research does this – phone surveys – sample only people in phonebook – external validity is limited 2 Ethics associated with Human Subjects • The unspoken subject-experimenter contract – Subject expectation is that experimenter will • give clear instructions • ensure safety & warn of dangers • inform subjects of the nature of the experiment – Experimenter expectation is that subjects will • cooperate • be honest (faithful) • In psychology, subjects frequently see experimenter not as a scientist but rather as a therapist Institutional Ethical Oversight • Institutional Review Board – research must be approved prior to conducting the research – approval does not lesson responsibility of the experimenter Basic Ethical Principles • Minimize harm to participants • Informed consent • Freedom to withdraw • Protection from harm • Confidentiality • Maximize benefit to science Informed Consent • Ss should be given a description of what they will do and possible problems (and detrimental effects), the purpose of the experiment • Ss must sign a consent form that describes risks or discomforts and explicitly states that – participation is voluntary – the subject may withdraw at any time without penalty – responses are confidential or anonymous • Deception – “cover story” used to minimize reactivity to experimental procedures – if used must provide a full debriefing! The Debriefing • As a part of informed consent, subjects should be told of the full nature of the study • Especially important if study causes temporary detrimental effects or uses deception • Goal: identify and remove misunderstandings • Opportunity to collect additional data • Opportunity to educate Freedom to Withdraw • Ss must be allowed to withdraw from an experiment at any time • Ss must KNOW they have the freedom to withdraw
