Research Design, Statistics, Tests & Measurements Flashcards
Mental Age
Age at which a person functions intellectually, regardless of their actual chronological age
Hypothesis
Tentative and testable explanation of the relationship between two or more variables
Variables
Characteristic or property that varies in amount of kind and can be measured
Operational Definitions
Define the variables in the experiment so that the variables are measured
Independent Variable
Variable whose effect is being studied and is manipulated by the experimenter
Dependent Variable
Variable is expected to change due to variations or differences in the independent variable
Correlational Study
Researcher does not manipulate the independent variable
True Experiment
Researcher uses random assignment for groups and manipulates the independent variable
Quasi - Experiment
Researcher manipulates the independent variable but does not use randomly assigned groups
Naturalistic Observation (Field Study)
Researcher does not intervene; measure behavior as it naturally occurs
Sample
Subset of a population
Random Selection
Each member of the population has an equal chance of being selected for the sample
Stratified Random Sampling
Assuring that each subgroup of the population is randomly sampled in proportion to its size
Between - Subjects Design
Each subject is exposed to only one level of each independent variable
Matched - Subjects Design
Experiment could match subjects on the basis of the variable that he wants to control
Population
The group the research wishes to generate her results to.
Representative Sample
Sample is a miniature version of the population
Within - Subjects Design (Repeated - Measures)
Pair each subject with themselves by using the same subjects in both groups
(2+ experiments with the same subjects involved and exposed to 2 + conditions)
Confounding Variables
Unintended Independent Variables
Control Group Design
Treating both groups equally except for the independent variable
Control group (no treatment) vs Experimental group (gets treatment)
Nonequivalent Group Design
Control group (no treatment) is not necessarily similar to the experimental group (gets treatment)) since the researcher does not use random assignment
Double Blind Study
Neither researcher who interacts with the subjects nor the subjects themselves know which groups received the independent variable or which level of the independent variable
Single Blind Study
Subjects do not know whether they are in the treatment or control group but the research does know
Demand Characteristics
Cues that suggest to subjects what the researcher expects from them
Hawthorne Effect
Tendency of people to behave differently if they know that they are being observed
Experimenter Bias
Experimenter’s expectations or attitudes that can affect results
Placebo Effect
A type of demand characteristic where a placebo has a beneficial effect on the subjects
Descriptive Statistics
Concerned with organizing, describing, quantifying and summarizing a collection of actual observations
Inferential Statistics
Researchers generalize (from sample to population) beyond actual observation;
Using a relatively small batch of actual observations to make conclusions about the entire population of interest
Measures of Central Tendency
- Mean
- Mode
- Median
Provide estimates of the average score
Mode
Value of the most frequent observation in a set of scores
Bimodal
Two values that are tied for being the most frequently occurring observation
Median
Middle value when observations are ordered from least to most or from most to least; this divides distribution in half (NOT the halfway point)
If there is an even # of data points - add the two middle most numbers and divide by 2
Mean
Numerical halfway point between the highest and lowest score; the arithmetic average
Sum of Observations
______________________
Number of Observations
Variability
Difference in scores
- if scores are all the same = 0 variability
- if scores are all different = high variability
Range
The smallest number in the distribution subtracted from the largest number
Standard Deviation
Measure of the typical distance of scores from the mean
Variance
The square of the standard deviation; A description of how much each score varies from the mean
Percentile
Percentage of scores that fall at or below the particular score
Z-Score
Indicates the number of standard deviations your score is away from the mean
Correlation Coefficients
Descriptive statistics that measure to what extent, if any, two variables are related
Positive Correlation
Change in the value of one of the variables tends to be associated with a change in the same direction of the value of the other variable
Negative Correlation
Change in the value of one of the variables tends to be associated with a change in the opposite direction of the other variable
Factor
Cluster of variables highly correlated with each other is assumed to be measuring the same thing
T-Test
Used to compare the means of two groups
Chi - Square Test
Test the equality of two frequencies or proportions
Analyses of Variance (ANOVAs)
For 2+ groups - used to compare the means of the groups
Reliability
Consistency with which a test measures whatever it is that the test measures
High Reliability = Measures are dependable, reproducible and consistent
Validity
Extent to which a test actually measure what it is puports to measure
Ratio Intelligence Quotient (IQ) Equation
Mental Age
__________________ x 100
Chronological Age
Personality Inventory
Self-rating device usually consisting of somewhere between 100-500 statements; subject determines if the given statements apply to them
**Scoring is Objective
Ex: Personality Tests
Projective Tests
Stimuli are relatively ambiguous; Test taker is not limited to number of responses. After given the stimuli the subject interprets what they see
**Scoring is Subjective
Ex: Rorschach Inkblot Test
