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Flashcards in Statistics & Research Design Deck (152)
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Qualitative Research

Tell when, where & how often things happen & looks at "why" & "how" to produce observations, notes & descriptions of behavior & motivation. (Quality of relationship, actions, situations or other phenomena) Methods: Interviews, Focus Groups, Reviews & Observations


Quantitative Research

Conducted to obtain numerical data on variables. Produces hard numbers that can be turned into statistics. There are 2 types: Non-Experimental (descriptive) - Conducted to collect data on variables [correlational & archival research, case studies & surveys] Experimental - Conducted to test hypothesis about the relationship between variables or the effects of 1 + IV on 1 + DV.


Steps for Planning & Conducting Experimental Research

1. Devel. Idea into a testable hypothesis (about the rel. btwn. variables) 2. Choosing an approp. research desing 3. Selecting a sample (ID target pop., determine how to select from pop. & select sample) 4. Conducting the study (Collect & record data for later analysis) 5. Analyzing the obtained data (analyze with approp. descriptive & inferential stats techniques) 6. Reporting the results



Any characteristic, behavior, event or other phenomenon that is capable of varying or existing in at least 2 different states, conditions or levels. Ex: Gender - Male/Female (when characteristics restricted to a single state/condition it's a constant. Ex: Gender - Male only)


Independent (experimental) Variable (IV)

Variable believed to have an effect on the dependent variable. It is manipulated in a research study to determine it's effects on the DV and must have 2 levels (2 points of comparison since possible to determine effects of an intervention when there is a comparison point) aka - "Treatment" or "Intervention" & symbolized by letter X Tip: "what is the effect of (IV) on (DV)?


Dependent Variable (DV)

Observed & measured in a study & is believed to be affected by the IV (depends on IV). can be considered the outcome of treatment; does not manipulate just observes and measures. Symbolized by the letter Y


Narrative Record

Method of defining & measuring variables related to behavior as it occurs. The record being a detailed written description or an audio &/or video recording.


Content Analysis

Method of defining & measuring variables related to organizing the data into categories that can be used to summarize & interpret information in a narrative record.


Protocol Analysis

Used to ID cognition's underlying problem solving & decision making. Involves recording a subject's verbalization's when instructed to "Think Aloud" while solving complex cognitive problems.


Interval Recording

Behavioral sampling that involves dividing a period of time into discrete intervals & recording whether the behavior occurs in each interval. Useful when the target behavior has no clear beginning or end.


Event Sampling

Behavioral sampling that involves recording each occurrence of a behavior during a pre-defined/pre-selected event. Useful for behaviors that occur infrequently or leave a permanent record (test or measure).


Random Assignment

Method of assigning subjects to treatment groups using a random method; aka "Randomization." Key component to True Experimental Research since it enables an experimenter to conclude that any observed effect on the DV was actually caused by the an IV rather than error.


Experimental Research

Involves conducting a study to test hypotheses about the relationship between the IV's & DV's. There are 2 types: 1. True Experimental Research (Random assignment) 2. Quasi-Experimental Research


True Experimental Research

Allows for greater control over the experimental situation & "Hallmark" is random assignment to different groups (different levels of the IV). Allows the experimenter to be more certain that subjects in different groups are initially similar & that any observed difference between the groups on the DV were caused by the IV. Ex: Tx Group vs No Tx Group


Quasi-Experimental Resarch

Involves testing a hypotheses about the relationship between the IV & DV yet has less experimental control since the experimenter can not control the assignment of subjects to a treatment group & must use pre-existing groups or a single treatment group. Ex: kids that attend 2 schools; use kids from school 1 as experimental group & kids from school 2 as control group.


Random Selection

Enables the investigator to generalize their findings from the sample to the population. Research does not have access to the entire population of interest & must draw a sample from that population. So that any observed relationship between variables in the sample can be generalized to the Population, the people in the sample must be as representative of the population as possible in terms of relevant characteristics such as age, gender & severity of symptoms.


Cluster Sampling

Entails selecting units or groups (clusters) of ppl from the population (schools, hospitals, clinics) & either including all individuals in the units or randomly selecting individuals from each unit (multistage). Useful when not possible to ID/obtain access to the entire population of interest.


Simple Random Sampling

Every member of the population has an equal chance of being selected for inclusion in the sample. (reduces probability of bias especially when its a large sample)


Stratified Random Sampling

When the population varies in terms of specific characteristic "strata" relevant to the research hypothesis, this will ensure that each stratum is represented in the sample by dividing the population into the appropriate strata & randomly selecting subjects from each stratum. (Ex: Gender, age, ED level, SES, racial/ethnic/cultural background)


Maximizing Variability Due to IV(s)

In conducting and experimental research study and experimenter wants a design that will maximize variability in the DV that is due to: -The IV -Control variability due to extraneous variables (systematic error) -Minimize variability due to random error


Systematic Error

A predictable Error


Extraneous (Confounding) Variables

Are a source of systematic error. It is a variable that is irrelevant to the purpose of the research study but confounds it's results because it has a systematic effect on (correlates with ) the DV.


Experimental Variability

Variability in the DV that is due to the IV is maximized when groups are made as different as possible with respect to that variable.


Random Error

Error that is unpredictable (random). Variability due to random error is minimized by ensuring that random fluctuations in subjects, conditions & measuring instruments are eliminated or equalized among all treatment groups. (Sampling error)


Randomization (Random Assignment of Subjects to Tx Groups)

Random assignment of subjects to different levels of the IV is considered the most powerful method of control because it helps ensure that groups are initially equivalent with regard to all known & unknown extraneous variables.


Holding the Extraneous Variable Constant

Eliminate the effects of an extraneous variable by selecting subjects who are homogeneous with respect to that variable (Shortcoming is that it limits the generalizability of the research results)


Matching Subjects on the Extraneous Variable

Useful for controlling extraneous variables when the number of subjects is too small to guarantee that random assignment will equalize the group in terms of an extraneous variable.


Blocking (Building the Extraneous Variable into the Study)

Subjects are not individually matched but are blocked (Grouped) in terms of their status on the extraneous variable & subjects with in each block are randomly assigned to one of the treatment groups.


Statistical Control of the Extraneous Variable

When an investigator has information on each subject's status (score) on an extraneous variable. The ANCOVA (analysis of covariance) or other statistical technique can be used to statistically remove the effects of an extraneous variable.


Internal Validity

The degree to which a research study can allow the experimenter to conclude that observed variations in the DV were caused by variations in the IV rather than by other factors.