Shared Flashcard Set

Details

Research Design
Research psychology flashcards
94
Psychology
Undergraduate 2
11/20/2008

Additional Psychology Flashcards

 


 

Cards

Term

 

IMC

Definition

 

Any IV with many values. 

You measure or count its level in each case

Term

 

ISP

Definition

 

An IV with few values. 

You partition your sample into groups, assigning cases according to their score on the variable.

Term

IXB

Definition

 

An IV with few values. 

 

You  create a few levels of this variable; then expose each case to one level (all cases at the same level are called a group or collection).

Term

 

IXW

Definition

 

An IV with few values.

You create the levels of this variable; then expse each case to every level of the IXB variable.

Term

DMC

Definition

 

A DV with many values. 

 

You measure or count its level in each case.

Term

DSP

Definition

 

A DV with few values. 

You partition your sample into groups, assiging cases according to their scores on the variable.

Term

MMC

Definition

 

A mediating variable with many values.

You measure or count its level in each case.

Term

MSP

Definition

 

A mediating variable with few values. 

 

You parition your sample into groups, assiging cases according to their scores on the variable.

Term

PMC

Definition

 

A precausal variable with many values.

 

You measure or count its level in each case.

Term

PSP

Definition

 

A precausal variable with few values. 

You partition your sample into groups, assiging cases according to theri scores on the variable.

Term

Types of Surpressed Variables

Definition
  1. SRA
  2. SPC
  3. SCA
  4. SSC
  5. SRM
  6. SCO
Term

Surpressed Variable

Definition

 

A variable that does not vary at all, or whose average value is equal across groups or conditions.

 

Because it is surpressed, this variable cannot play a role in any observed covariation among other variables in the study.

Term

W

Definition

Wild Card

 

A variable that is neither measure nor surpressed.  Thus you can neither study its role in affecting covariation among other variables, nor eliminate such influence.

Term

 

Factorial Design

Definition

An empirical study has a factorial design if...

  1. It includes at least 2 categorical IVs
  2. One condition within the study presents every possible combination of levels (one level from each IV)
  3. It includes at least one DMC or DSP variable
Term

Research Design

Definition

 

logical arrangement of variables in a study. every study has a research design.

 

strong designs allow relations among variables of interest to be assessed unambiguously and relations not of interest to be isolated or removed.

Term

3 Steps to designing new research

Definition
  1. Identify all variables
  2. Decide each variable's logical status and measurement status.  logival and measurement status indicate treatment mode.
  3. arrange the study's variables within a specific research design
Term

Logical Status

Definition

a variable's role in any causal interpretation the researcher intends to make of research results.

 

6 Statuses: I, D, M, P, S, W

Term

Additive Treatments

Definition

 

 

allow us to learn about how a variable covaries with other variables; how it functions as an aspect of psychology

Term

Subtractive Treatments

Definition

 

Suppress (neutralize/remove) the effects of variables in a study; as a result we cannot learn about such variables, but we can learn more about the other variables.

Term

 

EXPERIMENTS

Definition
  • IXB + (random assignment or counter-balanced assignment) + (DMC or DSP)
  • IXW + (DMC or DSP)
Term

A Correlation Matrix

Definition

A square matrix of statistics from a multivariate study.

 

Each variable occupies one row and one column of the matrix.

 

Each cell shows the value of a correlation coefficient between its tow and column variables.

Term
Parts of a Correlation Matrix
Definition
  1. Upper Right Triangle
  2. Lower Left Triangle
  3. Main Diagonal
Term

Upper-Right Triangle

Definition

Shows the values of rxy for each pair of variables

 

 rxy =Correlation coefficient

Term

 

# of Correlations

Definition

 

#Corrs=(#vars)(#vars-1)

          2

Term

 

Main Diagonal

Definition

The Main Diagonal can either...  

  • shows r= 1.00 (because any variable can predict its own scores with perfect accuracy)
  • cells are left blank b/c redundant to put 1.00
  • shows the reliability coefficient for each variable if known (will be strong positives) -- ie. measured variables twice and is degreee of test-retest
Term

 

Common

Variations

of a correlation matrix

Definition
  • upper-right triangle gives values of rxy; lower-left triangle gives N and the significance level for each value of r
  • upper-right and lower-left triangles display r values found in different groups or in different samples
Term

Hazard of Multivariable Studies

Definition

 

-May draw results that are correct for your sample but may not be otherwise (increases with more variables)

Term
Groups vs. Conditions
Definition

Groups: Sample divided into groups

Sample-> voting, consensus, individual

 

Conditions: Whole sample goes through each condition
Sample-> voting -> consensus -> Individual

Term

Suppressed Variable

Definition
  • Doesn't Vary (remains at fixed level) age
  • Varies at a fixed level (average level is same in different groups or conditions of the study)
  • Varies but doesn't influence other variables
Term

Pre-Causal

Variable

Definition

 

A variable that may covary with other variable(s); if it does, you lack sufficient evidence to identify either variables as a cause or effect of the other.

Term

Why Supress Variables?

 

Definition
  • is as important as manipulation and measurement.
  • a subtractive process that strengthens the interpretability of other relationships.
Term

 

MC

Definition

A Measured/Counted Variable

 

 

measures how much or count how many of the focal attribute(s) is/are present in each observation; a scalar variable

Term

SP

Definition

A Sample Partition Variable

 

assign each case in the sample to one category of this variable.  This partitions the sample into groups; each group includes all cases with the same attribute on the variable.

Term

 

Converting:

 

MC -> SP

Definition

Scores on a measured/counted variable can be used to divide a sample into groups. 

 

First transform scores on the MC variable into just a few (highly rounded) values; then assign each case to a group based on its (highly rounded) score

Term

 

Dichotomizing a Variable

Definition

common way to convert an MC variable into an SP variable.

 

Establish a cut-point value; call cases who score above it 'high' and those who and those who score below it 'lows'

Term

MEDIAN

SPLIT

Definition

most common way to dichotomize a variable. 

 

Process: Find the median then assign each case to a 'high' or 'low' group depending on whether it scored above ot below the median.

Term

XB

Definition

experimentally manipulated 'between groups' variable

 

researcher creates a categorical variable.  scores are merely labels for the levels of a treatment that was manipulated by the experimenter.

 

Logical status of XB variables is always "I". Each case is exposed to one level of the IXB variable; then its status is assessed on a DMC or DSP variable

Term

XB example

Definition

 

bake 3 batches of brownies: one usuing butter, one using vegetable shortening; one using fish oil.  Different groups of 10 people taste and then rate each batch.

Term

 

bake 3 batches of brownies: one usuing butter, one using vegetable shortening; one using fish oil.  Different groups of 10 people taste and then rate each batch.

Definition

 

XB example

Term

 

XW

Definition

 

experimentally manipulated "within subjects" variable

 

Same as XB except each case is exposed to all levels of the IXW variable, the DV is measured after each exposure

Term

XW example

Definition

 

bake 3 batches of brownies: one using butter, one using vegetable shortening, one using fish oil.  All 30 subjects taste and rate all three batches. (Probably should have people drink some water between tastings)

Term

 

bake 3 batches of brownies: one using butter, one using vegetable shortening, one using fish oil.  All 30 subjects taste and rate all three batches. (Probably should have people drink some water between tastings)

Definition

 

XW example

Term
Measurement Status
Definition

how scores are obtained on a variable. 

 

6 statuses: MC, SP, XB, XW, S, W

Term

I

Definition

Independent variable (I)

 

a variable is an independent variable (IV) if the researcher believes it controls- at least in part- the level of another measured variable in the study

Term

 

D

Definition

Dependent variable (D)

 

a dv is being studied in order to determine whether its level is controlled (at least in part) by another measured variable in a study

Term

 

M

Definition

mediating variable (M)

 

any variable that "carries" the influence of a cause to its effect.  Mediators are postioned in the middle of a causal sequence or chain; in A -> E -> B, E is a mediating variable

Term
Is an "I" variable always a cause?
Definition

 

NO. Whether or not an IV is a cuase depends on the study's results (and on the soundness of the study's research design).  IV means, in effect, "possible cause".

Term

The Logical Statuses are...

Definition
  1. I
  2. D
  3. M
  4. P
Term

The Logical-Measurement Statuses are...

Definition
  1. S
  2. W
Term

The Measurement Statuses are...

Definition
  1. MC
  2. SP
  3. XB
  4. XW
Term
Nuisance Variables
Definition

variables you do not want to learn about in a study, but should deal with anyway because they may 'matter' in your topic area

 

ie: 3rd variables, confounded manipulations

Term
Supressing Nuisance Variables
Definition

ensure all cases in our sample score the same on any nuisance variables

 

ex.s

  1. all words have 5 letters in word memory task
  2. same written text explanations to each partic.
  3. every partic. gets same effective dose of alcohol and is test exactly 30mins. later
Term
Suppression by Selective Sampling (SSS)
Definition

in building sample, select only cases with particular score (or cases that fall within a limited range on that variable).

 

Result: sample will not vary on that variable (or will vary on it less than does the population)

Term

Why Suppress?

Definition

 

suppressing nuisance variables clarifies relationships among other variables in the study

Term

When to Suppress?

Definition
  1. as you select sample (SSS)
  2. as you assign cases to groups/conditions (SRA, SCA)
  3. during the study's procedures (SPC, SRM, SCO)
  4. when you analyze the data (SCC)
Term

 

SSS

Definition

suppression by selective sampling

Term

SRA

Definition

suppression by random assignment of cases to conditions

Term

SCA

Definition

suppression by counterbalanced assignment of cases to conditions

Term

SPC

Definition

suppression by procedural controls

Term

SSC

Definition

suppression by statistical controls

Term

SRM

Definition

suppression by repeated measures

Term

SCO

Definition

suppression by counterbalanced ordering of stimuli

Term

bivariate correlational design

Definition
simplest of all empirical research designs that can assess covariation.  Find the scores of each case on two MC variables; correlate these variables; calculate r
Term
A study with n MC variables can generate ____ coefficients
Definition

#coefficients=(n)(n-1)

                    2

Term

Intact Groups Comparison Design

 

Definition

an existing ISP variable is used to assign cases to groups which are then compared on other (DMC or DSP) variables

 

ex.

men vs. women

Putnam's class vs. Templeton's class

Term

 

Sort-Of Intact Groups Comparison Design

Definition

researcher rounds scores on an IMC variable to just a few values which converts it to an ISP variable.  He partitions the sample into groups based on scores on that variable, and compares them on other (DSP or DMC) variables

 

All of bowdoin into groups by gpa (0-1, 1-2, 2-3, 3-4) and compares them on dependent variables

Term

Cross-Classification Design

Definition

Any research that uses a cross-classification table.  Place each case in one cell of each table, look for evidence of covaritation between the variables.

 

basically cross-tab tables

Term

Coefficient Comparison Design types

Definition

2+ DMC variables. Ho sets the value of a correlation coefficient at something other than rab =.00

  1. rab in different groups; study whether two variables are correlated to the same degree in different groups
  2. rab compared with rac; does A correlate equally with two other variables (B and C)? Null hypothesis says it does
Term
Some elaborate correlation-based designs and methods
Definition
  1. partial correlation anaylysis
  2. mediator analysis
  3. moderator analysis
  4. multiple correlation
  5. factor analysis
Term
Between-Groups Experiment
Definition

a family of research designs with three defining features...

  1. cases are assigned to groups randomly (or with counterbalancing)
  2. researcher manipulates at least one IV and exposes each case to one level of that IV
  3. at least one DMC or DSP variable is assessed after cases have experience the IV
Term
Treatment-Control Comparison Design
Definition

simplest experiment design with one IXB2 variable and one DMC or DSP variable

  • randomly assign cases to either the treatment group or the control group
  • expose cases in the treatment group only to the experimental stimulus
  • measure each case on the DV
  • if the groups score differently on the DV, conclude that the IV caused scores on the DV
Term

Ways to ensure IV's for groups ONLY differ on the DV in between-groups designs...

Definition
  • dummy/filler task: a hollow task for the control group to perform; similar to the treatment but lacking the true IV.  alcohol
  • sham surgery: surgery performed on control-group animals; duplicates surgery on treatment animals, but omits the actual 'treatment'
Term
Expectancy Effect
Definition

when subjects have expectancies about what will happen in a study, those beliefs can influence thier behavior, independent of any effect of the actual treatment

How to Handle:

  • keep subjects unaware of procedure as much as possible.
  • compare behavior of people who knowingly experience the treatment with people who falsely believe they've experience the treatment.
Term

PLACEBO

Definition

 

a 'pretend' treatment that leads to the participant to believe (expectancy) he has been given the real treatment

Term

Placebo Designs

Definition
experiments that include one or more placebo conditions, in which you lead subjects to believe they are receiving a treatment even though they are not
Term

Balanced Placebo Design

Definition

The Groups:

  1. subjects correctly believe they receive tment
  2. subjects falsely believe the tmt (actually placebo)
  3. subjects correctly believe they are in control grp
  4. subjects falsely believe are in control grp (actually get tment)
Term
Treatment/Control with Pretest
Definition

randomly assign cases to tment groups, then premeasure the DV in all cases.  Manipulate the IV then re-measure the DV.  Compare measurements.

 

demonstrates that the tment and control groups were equal on the DV before the experiment began.  can also assess whether DV scores change over time, regardless of the effect of the IXB

Term
Multiple Treatments Design
Definition

experiments that compare two ore more treatments to the same control group.

 

Benefits:

  • you get 'double use' from control group
  • can directly compare the effects of the two(or more) treatments
Term
Factorial Experiment
Definition
a multiple-treatment experiment with at least two categorical IVs, in which every combination of levels of the IVs is created and its effects on a DV tested
Term

Quasi-Experiment

Definition

 empirical research that resembles an experiment, but have less control of some aspects of study. provide suggestive evidence of cause-effect relation. useful when cannot perform true experiment.

 

ie, train experiment

Term

Intact-Groups Quasi-Experiment

Definition

groups were not created by random or counter-balanced asignment of cases to conditions. if groups created by IXB perfom differently on DV then researcher cannot be sure whether IXB (or preexisting & unmeasured differences between cases in different treatment groups caused the gorup differences on the DV.

Term

 

Within-Subjects/ Repeated-Measures Designs

Definition

a study in which a dv is measured multiple times in the same cases.

Benefits:

  • sample size is N for every level of IXW providing more data than b/ween grps design
  • repeated measurement of a DV in the same cases lets you surpress subject variables. SRM
Term

 

Within-Subjects/ Repeated-Measures Experiments

Definition
  • study has one group with all the cases
  • expose each case to one level of IXW, then measure DV
  • expose to another level of IXW; measure
  • repeat for rest of IXWs
  • compare sample's performance on the different measurements of the DV
Term

Repeated-Measures in a Between-Groups experiment

Definition
the treatment/control experiment with pretest experimental design uses repeated measurement of the DV; you compare each case's pre-IVs with post-IV scores
Term

 

Order Effects

Definition

 

how the order of conditions effects the study.

 

solve by switching up the order.

Term

 

Factor

Definition
any IV that contributes to a factorial design.  All factors are IVs.  Not all IVs are factors.
Term

Cell

Definition
each combination of one specific level of every factor variable creates one cell in the design
Term

for a "3 X 3 X 2" factorial design

  1. # of Factors?
  2. # of levels for each factor?
  3. # of cells in design
Definition
  1. 3
  2. 3, 3, and 2
  3. 18
Term

Cell Means

Definition
the mean DV score among all the cases with the cell's combination of scores on the factors
Term

Marginal Mean

Definition

the mean DV score among all cases at one level of the factor

 

(end of the rows)

Supporting users have an ad free experience!