Documents about Confounding Variables

  • 5 Pages

    week8

    Purdue, RHIT 501

    Excerpt: ... RESTAURANT, HOTEL, INSTITUTION, AND TOURISM MANAGEMENT 590R Research Methodology Class Lecture Notes - Week 8, Session 16-18. Constructing a Procedure A) Types of Variables The variables discussed in the statement of purpose and hypotheses can be divided into four types: 1. independent variables 2. dependent variables 3. extraneous or confounding variables 4. control variables One reason for discriminating among the types of variables is that it helps in accurately selecting the appropriate statistical analysis. It also enables the researcher to construct a valid research design. This allows the researcher to apply the scientific method so as to minimize any error or bias. 1) Independent and Dependent Variables - The one or more variables that the experimenter selects or manipulates in order to determine its effect on other variables is called the independent variable. The independent variable is independent of any subject's behavior; it is a situation, characteristic, or phenomenon within which the subject ...

  • 2 Pages

    17

    USC, COMM 202

    Excerpt: ... Experimental Designs Reviews & More 9/17/08 Note: for test, know how to id the different research methods. Experimental Methods -When are experiements appropriate? - When your focus is a how an iv affect an dv. - Trying to explain causal explanation Basic Setup of an Experiment - We try to manipulate iv to determine affect on dv. Confounding Variable - What are they? - A variable that can explain what is seen. - What do you want to do with them in the context of an experiment? - Which types of validity of an experiment/study do confounding variables threaten? - It could affect the way the experiment happens/the design. - INTERNAL validity? Ruling out Alternative Explanations - Internal Validity- Have I ruled out or controlled for other reasons that could be giving me these results? - External Validity- How research from one internally valid study might be generalizable to another context. Tension between external and internal validity. - As you increase external validity, you open threats to internal validity ...

  • 1 Pages

    2ndwritingassignment.winter2004

    UCSD, PHIL 12

    Excerpt: ... Second Writing Assignment, Winter 2004 Sections A and B: Monday afternoon sections (Sophia Efstathiou, TA) Explain what a confounding variable is. Give an example of an experiment (actual or made up) where a confounding variable compromises the inter ...

  • 1 Pages

    hw6and7

    Penn State, STAT 200

    Excerpt: ... ink is represented by this sample? In an observational study, there is a risk of confounding variables . Does the story mention whether the researchers controlled for any confounding factors? If so, what were the confounding variables ? If not, what confounding variables should they have controlled for? Note at the bottom of the web site page, there are links to stories from previous days. HOMEWORK 7 Turn in answers to the Lab 11 activities. If you need a fresh copy of Lab 11, you can find one at the course web site. The direct link to the file is: www.stat.psu.edu/~rho/stat200/lab11.pdf ...

  • 38 Pages

    290a_June11

    Arizona, PSYC 290 A

    Excerpt: ... ffee & nice barrista -> no crankiness Can we tease apart coffee type (caf or decaf) and friendliness of barrista (rude or nice)? Regular coffee & rude barrista -> crankiness Regular coffee & nice barrista -> crankiness Decaf coffee & rude barrista -> no (or little) crankiness Decaf coffee & nice barrista -> no crankiness The effect of the friendliness of the barrista can be eliminated, thus it was a confounding variable MEDIATING vs. CONFOUNDING VARIABLE Mediating variables cannot be eliminated (can be varied - higher arousal) Confounding variables can be eliminated if identified and controlled for (regular coffee still made you cranky, regardless of the barrista's friendliness) DIRECTIONALITY PROBLEM Poor reading ability and erratic eye movements Schools concluded that deficient oculomotor skills caused reading problems Schools erroneously trained such readers to improve their eye movements Actually poor word recognition and comprehension causes erratic eye ...

  • 2 Pages

    mod2.3

    Idaho, PSYC 101

    Excerpt: ... ariable: Behavior that is measured or observed Example: Amount of aggressive behavior after watching the show Exp: M X M M Hypothesis tested by observing effect of manipulating independent variable 3 Contr: M 4 Psyc 100 Introduction to Psychology How Can the Researcher Be Sure of Cause & Effect? Experimental group and control group must be similar except with regard to independent variable There must be no confounding variables Confounding variables : Uncontrolled variables that change along with the independent variable Psyc 100 Introduction to Psychology Fig. 2.8 Random assignment: Each participant has an equal chance of ending up in any group or condition in the experiment Helps ensure that overall, experimental and control groups are similar 5 6 1 Psyc 100 Introduction to Psychology Psyc 100 Introduction to Psychology Fig. 2.9 Expectancies and Biases in Experimental Research Participants may guess what the researcher expects to find Then, may change behavior to f ...

  • 2 Pages

    p_intval

    UNL, UNIT 350

    Excerpt: ... Prelude to Internal Validity Types Of the four types of validity (Measurement, External, Internal & Statistical Conclusion), we will be most concerned with External Validity and Internal validity. Each of these has different types or components with ...

  • 3 Pages

    07.10.29.experimentalDesign-experiments.ppt

    UH Clear Lake, PSYC 6036

    Excerpt: ... Quiz Experiments-Design Overview Administrative Experimental Design Conducting Experiments Next time 1 Administrative Introductions due today One member of each group should have submitted the Introduction through WebCT Experimental Design Experimental design Increases internal validity control for confounding variables so only difference between groups is due to IV Random assignment prevents any systematic differences between the groups Options for measures Post only test Pre test-post test (repeated measure) Different types of designs Independent (between) group design Easier to conduct Can be tough to make the conditions *completely* identical except for the IV. Repeated measure design Easier to find an effect-reduce variability Order effects can impact outcome Counterbalancing: Full and Latin square 2 Other designs Cross-Sectional studies Pros: easier to do, less expensive Cons: often cannot identify ...

  • 4 Pages

    Psyc 103 Lecture 2

    UCSD, PSYC 103

    Excerpt: ... ing variables Give 125 study guides to random students "If you use that study guide, you will 100% correct on the quiz next week?" power of suggestion, "experimental bias" "demand characteristics" o understands demands and tries to do it to make experimenter happy o purpose- identify cause and effect o advantages: precise control, ID cause and effect o disadvantages: ethical concerns, practical limitations, artificiality of lab conditions, confounding variables (any variable that the experimenter cant control and affect the results), biases (experimenter and participant) Biases Blind? Double-blind? o Ben ,n Willard (two blind rats) o Half of rats injected with memory drug, half with saline o Numbers tattooed on ears, odd numbered were getting drugs and even numbers were getting placebo o Were some difference in they way they measured Habituation Studies o Mom was tilting infant to look at the right information o Participant bias More (critical) experimental jargon: Informed consent Debriefing o Take ...

  • 4 Pages

    sm_chapter_11

    Penn State, STAT 100

    Excerpt: ... CHAPTER 11 SOLUTIONS AND MINI-PROJECT NOTES CHAPTER 11 RELATIONSHIPS CAN BE DECEIVING EXERCISE SOLUTIONS 11.1 Both firewood sales and cough drop sales are likely to increase during the cold season. No, it does not imply that fires cause coughs! No, you wouldn't necessarily conclude that walking causes lower weight. People who prefer to exercise (walk) may also be people who keep their weight under control, eat less fat, and so on. Reason 1 could be possible but isn't likely, that milk-drinking alone is responsible for low risk of stroke. Reason 2 is not likely, since it would say that a low risk of stroke causes people to drink milk, and vice versa. People don't usually even know whether or not they are at risk for strokes. Reason 3 could be possible, that milk-drinking is one of many factors that reduces the risk of a stroke. Reason 4 is quite likely, that confounding variables exist. One example is general good diet and good health, which leads to reduced stroke risk. Reason 5 is likely, that both reduced ...

  • 1 Pages

    KeyTerms3

    Penn State, STAT 200

    Excerpt: ... Key Terms for Chapter 3 Section 3.1 Descriptive Statistics Inferential Statistics Fundamental Rule for Using Inference Section 3.2 Observational Study Randomized Experiment Treatments Experimental Units Subjects Population Sample Simple Random Sample ...

  • 2 Pages

    PIA! # 1

    Rhode Island, PSYCHOLOGY 143

    Excerpt: ... _ 3. Based upon what you observed, identify two variables that will probably be shown to be correlated in this study. _ _ 4. Do you expect a positive or negative correlation? Why? _ EXPERIMENTAL? _ Based upon what you observed, what was an important independent variable in this study? Expecting Parents, pregnancy _ What was an important dependent variable? Martial Satisfaction after pregnancy or the presence of a newborn 5. What were the limitations of the research in which you participated and how would you improve upon the procedures used in this study? (For example, were there any potential confounding variables that remained uncontrolled? Explain your answer.) This experiment had some confounding variables , one being that the researcher was not aware to whether or not the parents planned to have a baby or it was a surprise that could affect moods and the satisfaction they feel on the marriage. T ...

  • 9 Pages

    CH 3 intro bb

    Tulane, PSYCH 101

    Excerpt: ... CH3: NATURE, NURTURE, AND HUMAN DIVERSITY Genes Chromosomes DNA How genes affect behavior Proteins Polygenic influence Genotype Phenotype Behavior Genetics Heritability Selective Breeding Human Studies Family studies, confounding variables Twin studies Identical and fraternal twins Confounding variables Adoption Studies Adopted twins Confounding variables Interpreting Behavior Genetics Findings Group Differences Heredity and Environment Interact Environmental influences on human behavior Gene-Environment Interactions Environment acts on genes Affects if genes are expressed Affects how genes are expressed Genes act on environment Passive genotype-environment correlations Evocative genotype-environment correlations Active genotype-environment correlations Evolutionary Psychology Natural Selection Adaptive Behaviors Depends on environment Gender Mating strategies Short-term vs long-term Evidence M ...

  • 35 Pages

    103Chap5

    Humboldt State University, YGK 1

    Excerpt: ... g, Inc. 8 Two reasons why we must sometimes use an observational study instead of an experiment . 1. It is unethical or impossible to assign people to receive a specific treatment. 2. Certain explanatory variables are inherent traits and cannot be randomly assigned. Copyright 2005 Brooks/Cole, a division of Thomson Learning, Inc. 9 Confounding Variables A confounding variable is . related to the explanatory variable, and affects the response variable. The effect of a confounding variable on the response variable cannot be separated from the effect of the explanatory variable on the response variable. Confounding variables are a bigger problem in observational studies. Researchers try to measure possible confounding variables and see if related to the response variable. Copyright 2005 Brooks/Cole, a division of Thomson Learning, Inc. 10 Example: Confounding Variables Study of the relationship between smoking during pregnancy and child's subsequent IQ a few years after birth. Explanatory v ...

  • 1 Pages

    validity_net

    UNL, UNIT 350

    Excerpt: ... pulation - Participant Sampling Target population Sampling Frame Selected Sample Data Sample Complete or Purposive Researcher-selected or Self-selected Simple or Stratified Attrition Design BG Choices we make influence Internal and External Validity ! Participants representation vs. control True Experiment Non-experiment J L WG J L Initial Equivalence Participant Assignment RA of individual participants by the researcher before manipulation of the IV - best but not a guarantee Without proper RA all subject variables are potential confounds Subject constants can't be confounding variables Subject variables that are equivalent across IV conditions are control variables Subject variables that are nonequivalent across IV conditions are confounding variables even if RA was used (remember RA doesn't always work) Setting Laboratory, Structured or Field ? Setting representation vs. control Task-Stimulus representation vs. control Ongoing Equivalence Procedural Standardization On ...

  • 1 Pages

    validity_net

    UNL, PSYCH 941

    Excerpt: ... pulation - Participant Sampling Target population Sampling Frame Selected Sample Data Sample Complete or Purposive Researcher-selected or Self-selected Simple or Stratified Attrition Design BG J L WG J L Choices we make influence Internal and External Validity ! Participants representation vs. control True Experiment Non-experiment Initial Equivalence Participant Assignment RA of individual participants by the researcher before manipulation of the IV - best but not a guarantee Without proper RA all subject variables are potential confounds Subject constants can't be confounding variables Subject variables that are equivalent across IV conditions are control variables Subject variables that are nonequivalent across IV conditions are confounding variables even if RA was used (remember RA doesn't always work) Setting Laboratory, Structured or Field ? Setting representation vs. control Task-Stimulus representation vs. control Ongoing Equivalence Procedural Standardization Task/Stimulus ...

  • 2 Pages

    secondwritingassignment.w07

    UCSD, PHIL 12

    Excerpt: ... nd Reporting) that 75% of self-described Fox News viewers believed in 2003 that Saddam Hussein was at least partly responsible for 9/11. Ellie agreed with FAIR that watching Fox News causes people to believe this. Ellie then developed the general hypothesis that watching Fox News causes people to agree with the Bush administration's policies. Design an experiment to test Ellie's hypothesis. Briefly describe the relationship between internal validity and confounding variables . Describe how you controlled for one confounding variable and point out one potential confounding variable you haven't controlled for. Section A03 Design the best experimental study you can to determine whether ingesting caffeine is a cause of enhanced athletic performance. Discuss all the critical factors involved in designing a good experiment, including how possible confounds will be controlled for, and defend the choices you make in designing the study. Identify the conditions under which you will be able to conclude that using caff ...

  • 2 Pages

    Study guide for week 1

    Lehigh, PSYC 121

    Excerpt: ... endent Variable (DV) Independent Variable (IV) 13 13 3 Class Notes (cont.) Random assignment Confounding variables Experimenter effects Correlation (positive and negative) Reverse causality problem 3rd variable effect Contact hypothesis Jigsaw classroom ...

  • 1 Pages

    E1RevF04

    Maryville MO, PS 1000

    Excerpt: ... Review Exam 1 Format: 45 questions, 2 pt each. Multiple Choice Chapters covered: 1, 2, 3, 4 ONLY Chaps 1 & 2: you are responsible for All; Chap 3: p69-70; Chap 4: p96-117. LECTURE:BE ABLE TO DEFINE ALL THE TERMS LISTED BELOW I. Intro and Methods Scientific Method: way of conducting research to minimize bias in observation and testing Biases: Hindsight, selective recall, gambler's fallacy, confirmation bias, etc. Types of Research Designs: Pros and Cons; Definitions 1. Case Study 2. Naturalistic Observation 3. Survey 4. Correlational: Positive vs. Negative; Strength 5. Experiment: Hypothesis, Independent , Dependent, and confounding variables 6. Quasi-experiment II. Techniques 1. Natural experiments 2. Lesion 3. Stimulation 4. Recording: EEG; Single-unit 5. Imaging: Pet; CAT; MRI; fMRI III. The Brain A). Organization of the Brain : Forebrain; Midbrain; Hindbrain 1. Cortex: 2. Lobes and their Function: Frontal; Parietal; Temporal; Occipital B). Specialized Brain 1. Split Brain Studies: Lateralization of Fun ...