Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Research Methods in Psychology The Experiment • Only research method capable of showing cause and effect Experimental Method • Review Literature of Past Research • Formulate Hypothesis • Design Research/Study Method (naturalistic observation, case studies, surveys, experiments, etc) • Collect the Data • Analyze the Data • Report the Findings (journal, critique, replicate) • Draw Conclusion or Theory on Explanation of Findings Hypothesis • A statement about the relationship between two or more variables • Must be testable and refutable • Instead of proving the hypothesis, science usually tries to disprove a null hypothesis. Null Hypothesis (H0): opposite of hypothesis Hypothesis Example: Statistical Significance : 95% not due to chance H0: Gender does not have an effect on spatial ability H1: Gender has an effect on spatial ability Variables • Independent Variable (I.V.): manipulated by experimenter • Dependent Variable (D.V.): MEASURED variable influenced by independent • Operational definition • Confounding/extraneous variables Control Group • No treatment or placebo • Serves as basis for comparison • Serves to eliminate alternative explanations Population – The larger group of people from which a sample is drawn Sample: Representative of the population Two ways to get sample Random: Every member of the pop has = chance Stratified: Sample is put together by picking a group statistically equal to the population Control Measures • Counterbalance: controls for order effects • Single-Blind: subject unaware of assignment • Double-Blind: subject and experimenter unaware of placement • Randomization – From population (sample) – From assignment to groups (assignment) Other Research Methods Ex Post Facto (after the fact) - Independent variable already present - Not a true independent variable, no cause and effect - Often used due to ethical concerns Naturalistic Observation - Natural setting: behavior is not interfered with or altered Survey Method - Gathers data on attitudes and behaviors. Case Study - Intense study of an individual Statistics Descriptive Statistics Organize and summarize data Central Tendency: mean, median, mode Standard deviation: variation in data Range: distance from smallest to largest Inferential Statistics Interpret data and draw conclusions Used to test validity of hypothesis (t-test) Standard Deviation Statistical Significance • Probability results are due to chance • Inferential stats (t-test) are used to check for either a 5% (p<.05) or 1% (p<.01) level of significance. Lottery tickets 14, 3, 27, 41, 18 1, 2, 3, 4, 5 Coin flips HHHHHHH or HHTHTHT More likely? Bell or Normal Curve 68% are within One standard deviation from mean 95% are within Two standard deviations from mean Measures of Central Tendency A Skewed Distribution Skews Correlation A statistical value of the relationship between two variables Positive Correlation As one number increases, the other increases. Ex: Study time to GPA Negative Correlation As one number increases, the other decreases. Ex: Absences to GPA No Correlation Variables do not affect one another in a significant way Ex: Height to GPA Correlation Coefficient • Ranges from -1.00 to 1.00 • Zero is no relationship • -0.85 is a stronger relationship than .34 • CORRELATION IS NOT CAUSATION!! (i.e. Just because two variables have a correlation does not mean one causes the other) CORRELATION IS NOT CAUSATION!!! • People that floss everyday live 3 years longer than those that do not. • Red wine drinkers live longer than those that do not drink red wine. • As speed limits increased on America’s highways, the death rate went down. • Women with breast implants commit suicide 3 times as often as those without breast implants. • Children who are played Mozart in the womb have higher IQ’s. • Marijuana users in youth are more likely to have mental illness as adults. • As ice cream sales increased, so did shark attacks. • More TV’s per person in a country, the longer people live. Illusory Correlation Ways to Study the Brain CT “cat” Scan: Computerized Axial Tomography x-ray of the brain MRI: Magnetic Resonance Imagingexcellent 3d image using magnetic fields fMRI: Functional Magnetic Resonance Imaging 3d image and shows blood flow in brain PET Scan: Positron Emission Tomography Scan Uses radioactive material in blood to show brain activity EEG: Electroencephalograph- brain waves activity CT Scans: An x-ray of the brain. A CT scan is essentially a computerized assembly of several x-ray images taken from a series of different angles. With a CT, the resolution is much better than conventional x-rays, and the detail that can be seen is much greater. CT Scans PET Scans P E T S C Normal Brain ADHD Brain A N S Brain Development in First Year of Life 5 MRIs 3 Post Contrast sagittal T1 Weighted M.R.I. 2 Section at the level of Foramen Magnum 1 Answers 4 1. Cisterna Magna 2. Cervical Cord 3. Nasopharynx Fig. 1.1 Post Contrast Axial MR Image of the brain 4. Mandible 5. Maxillary Sinus Flaws in Research • • • • • • Sampling Bias Overgeneralization Placebo effect Hawthorne/Barnum effect Demand Characteristics Experimenter Bias Ethics in Research • Participants are free to withdraw at any time • No undo stress • Subjects informed of significant factors that may influence their willingness to participate • Subjects should be debriefed • Ethical treatment of animals • Generally research goes before a review board for approval Evaluating Research STRENGTHS AND WEAKNESSES OF Experiment Correlation Surveys Naturalistic Observation Case Studies