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| Case Studies | research technique in which one person is studied in depth in hope of revealing universal principles EX Phineas Gage |
| Central Tendency | Describes average of a distribution. Median is middle score when data is ordered by size. Mean is arithmetic average of scores. Mode is most frequent score, bimodal distribution has 2 most frequent scores, multimodal distribution has 3 or more. |
| Confounding Variables | Factors that cause differences between the experimental group and the control group other than the independent variable. Example: Experimenter bias (also called expectancy effect)--occurs when a researcher's expectations about the outcome of a study influence the results. |
| Descriptive Statistics | Numbers that summarize a set of research data from a sample.Can be pictured as histogram or frequency polygon. |
| Ethical guidelines For Human Research | 10 Informed consent 2) Voluntary participation 3) Debriefing 4) Confidentiality |
| Experiment | Research method that involves manipulation of an independent variable (IV) under controlled conditions and measurement of its effects on a dependent variable (DV). Only method that can establish cause and effect between IV and DV. |
| Experimental Group | Group that you experimenting on; receives the independent variable (IV) |
| Hypothesis | Prediction of how 2 or more factors are likely to be related. Can be phrased as "If …, then …." statement. Often called "an educated guess".An experiment tests a hypothesis. |
| Inferential Statisctics | Statistics used to interpret data and draw conclusions.● Uses rules to evaluate probability that a correlation or difference between groups reflects a real relationship, not just chance (p)is the measure of real difference, p < .05 or p < .01 needed. |
| Naturalistic Observations | Observing & recording behavior in naturally occurring situations w/o trying to manipulate and control the situation |
| Normal Distribution | Represented by a normal curve (upside down U shape)-symmetric with mean, mode, and median the same score; 2 sides are mirror images. ● Represents data about how most human traits are distributed through population. Examples: SAT,IQ, |
| Placebo | Physical or psychological treatment given to the control group that resembles the treatment given to the experimental group, but contains no active ingredients. Placebo effect--response to belief that the IV will have an effect, rather than the actual effect of the IV. |
| Population | All of the individuals in the group to which the study applies.A sample is a subgroup of the population that participates in the study. |
| Quantitative Data | Information can be reported as numbers for ease of handling. Nominal scale uses numbers to name something, can be used to count cases.Ordinal scale can be ranked, ordered. Numbers cannot be averaged. |
| Quasi-Experiment | Measurement of DV (dependent variable) when random assignment to groups of a randomly selected sample is not possible. Often applies to studies involving sex or age of participants. Can suggest cause and effect. |
| Random Assignment | Division of the sample in an experiment into groups so that every individual has an equal chance of being put in any group or condition.Is not possible for studies dealing with differences between sexes or age groups. |
| Random Selection | Choosing of members of a population so that every individual has an equal chance of being chosen for a sample. |
| Reliability | Consistency or repeatability of results. Split halves reliability compares scores on one half to the other half. Test retest reliability compares scores on the same test taken at different times. Interrater reliability compares scores by different scorers of the same tests. |
| Skewed Distribution | Distribution with most scores squeezed to one end, few scores stretch out like tail. Skew named for direction of tail. Negatively skewed--skewed to left. Positively skewed--skewed to right. Mean pulled in direction of tail away from median; median measures centrality best. |
| Surveys | descriptive method; uses questionnaires or interviews |
| researcher bias | tendency for researchers to look for evidence that supports their hypothesis & ignore contradictory evidence |
| Participant bias | tendency for research participants to respond in a certain way because they know they are being observed |
| Correlation Studies | researchers observe or measure a relationship between variables |
| Correlation coefficient | a number value that indicates the strength and direction of the relationship between two variables |
| Positive correlation | +1.00 (closest to it); means 2 variables move in the same direction. Ex. Positive relationship between smoking & lung cancer. |
| Negative correlation | -1.00 (closest to it); means 2 variables move in opposite directions |
| Zero correlation | indicates there is NO relationship between 2 variables Ex. hat size & shoe size |
| Longitudinal study | studies a single individual or a group over an extended period of time. Provide in depth information but can be expensive & time-consuming |
| Cross-sectional study | compares individuals at various ages at ONE POINT in time. (one and done) |
| Random assignment | Assigning participants to experimental and control groups by chance |
| Dependent variable | what is being measured in an experiment; the research variable that "depends" on the independent variable |
| Operational Definitioins | statement of your procedures; identifies the IV & DV, sampling & assignment |
| Mean | the average; sum of a set of scores divided by the number of scores |
| Median | the middle score; score that divides a frequency distribution exactly in half; so that the same number of scores lie on each side of it |
| Mode | the most frequently occurring score |
| Normal distribution | forms a a bell-shaped or symmetrical curve (upside down U) |
| 68-95-99.7 Rule | means 68% of all scores fall within one standard deviation of the mean (average); Approx. 95 % of all scores fall within two standard deviations of the mean; 99.7% of all scores fall within three standard deviations of the mean |
| Standard deviation | shows how far scores vary from the mean (average) score |
| Ethical Principles for Animal Research | 1) Research must have a clear, scientific purpose 2) Provide humane living conditions for animals 3) Legally obtain animals 4) Least amount of suffering |
