Shared Flashcard Set

Details

Foundations of Measurement
Exam 1 Study Guide
46
Psychology
Graduate
02/16/2013

Additional Psychology Flashcards

 


 

Cards

Term
Reliability
Definition
The quality of a test score that suggests it is 1) sufficiently consistent, and 2) relatively free of measurement error.
Term
Error
Definition
Difference between observed score and true score. Factors that affect observed score are due to measurement error.
Term
Construct
Definition
An abstraction, used to unify or produce responses meausured in an assessment.  Construct produces behavior
Term
Behavior
Definition
Discrete events, observable to the self or other, an assessment of performance.
Term
Assumptions of Traditional Measurement Theory
Definition

1. Important psychological processes CAN be measured.

2. Construct produces behavior on measure.

3. Variations in scores represent "true" differences among individuals. 

4. All scores contain error.

5. Obtained score = true score + error

6. True score is constant.

7. Error is random.

8. Scores represent an underlying process (construct) that generates behavior.

9. What the measure assesses is more important than the measure used to assess it.

10. Construct cannot be fully operationalized by a measure, even in theory.

Term
Measurement problems common to psychological assessment
Definition

1. No single approach to the measurement of any construct is universally accepted.

2. Psychological measurements are based on limited samples of behavior.

3. Measurement is always subject to error.

4. Lack of well defined units

5. Psychological constructs cannot be defined only in terms of operational differences.

Term
Different forms of reliabitity
Definition

Test-restest

Alternate forms

Split-half

Internal Consistency

Inter-rater

Term
Test- Retest Reliablity
Definition

Purpose: to determine whether scores on one test are comparable over time.

 

Source of Error: changes over time- life changing events, maturation, etc

Term
Inter-Rater Reliability
Definition

Purpose- Are scores produced by different raters consistent?

 

Source of Error- scorer differences, human judgement

Term
Alternate Forms
Definition

Purpose: Are scores produced by different versions of the same test consistent?

 

Source of Error: item sampling, changes over time

Term
Split-half Reliabitlity
Definition

Attempts to assess for item inconsistency, concerned with the extent to which scores produced by half of the items are consistent with scores produced by the other half.

 

Source of Error: item sampling, nature of split

Term

Internal Consistency

 

Definition

Tests whether each item correlates positively with all other items

 

Source of Error: item sampling, test heterogeneity

Term
Problems with Alpha
Definition
1. On long tests, alpha can be misleadingly high.
2. High alpha can mask bad items
3. Very high alpha could also mean that the operationalization of the construct is too narrow.
Term
Ceiling Affect
Definition
Setting an upper limit on one variable. By setting an upper limit on Variable x, subjects can continue to have higher scores on variable y, but they are RESTRICTED on Variable x. The ceiling on variable x is causing a lower correlation than if subjects could continue to have high scores on variable x.
Term
Standard Error of Measurement
Definition

Represents the standard deviation of a hypothetical distribution if a subject were to take a test an infinite number of times. 

 

As the reliability coefficient of a test increases, SEM decreases. SEM gives a Range in which a true score is likely to fall within a given probability (confidence interval). 

 

Multiply SEM by 1.96 to get a 95% confidence interval

Term
Kuder Richardson (KR20)
Definition
for internal consistency for DICHOTOMOUS variables, used less than Cronbach's alpha
Term
Cronbach's Alpha
Definition

internal consistency among ALL items

 

The method used depends on the PURPOSE of obtaining a measure, and the way the measure will be USED.

Term
Sources of Error Variance in Measurement
Definition

Test construction (item selection, instruction)

test administration/environment

test scoring and interpretation

Mood, hunger, motivation, etc

 

Term
Systematic Measurement Error
Definition
When a test systematically measures a trait besides the trait on a test
Term
Measurement Error
Definition
Any fluctuation in scores that result from factors related to the measurement process that are irrelevant to what is being measured.
Term
True Score
Definition
the mean of a hypothetical distribution of scores that would be obtained if a person took the test an infinite number of times. You can used obtained score to estimate true score.
Term
Correlation Coefficient
Definition
index of the strength of the relationship between two variables. Correlation tells the degree and direction.
Term
What are the three conditions for conducting Pearson's R correlation?
Definition

1. Relationship between the variables is LINEAR.

2. The two variables are CONTINUOUS.

3. The pairs of observation are INDEPENDENT of one another.

Term
Significance and what does it depend on?
Definition

Is the relationship reliably different from zero??

 

Significance depends primarily on SAMPLE SIZE.

Term
Magnitude and what does it depend on?
Definition

The STRENGTH of the relationship between x and y.

 

Depends on the HETEROGENEITY of a sample, not the N.

 

Look at significance first, then magnitude!

Term
Three Factors that Affect Alpha
Definition

1. Content homogeneity of items

2. Nature of construct being assessed: unidimensional vs. multidimensional

3. Number of items. More items = more reliable score.

Term
Ceiling/floor effect
Definition
When a variable is measured that has a ceiling or a floor, we obtain a lower correlation coefficient than if the variable were measured without a floor or ceiling.
Term
How to Detect Restricted Range
Definition
Look at the frequency distribution of the variables, Standard deviation of your scores compared with those of other researchers.
Term
What factors can contribute to range restriction?
Definition
Bad luck recruiting, sample selection criteria
Term
Properties of Normal Curve
Definition
Bell-shaped
bilaterally symmetrical
Tails never touch
Baselines stretch to infinity
Uni-modal (single point of maximum height)
Has a mean, mode, median that coincide at the center
Standard deviations are positioned at equal distances along the x axis.
Term
Uses of Normal Curve
Definition
Descriptive
Inferential
Estimating population parameters
Term
Nominal
Definition
Name, numbers are used instead of words, identity. SSN, football players jerseys, numerical codes for sex or psychiatric diagnosis
Term
Ordinal
Definition
Rank, percentages. Does not assume equal intervals and does not specify distance between intervals
Term
Interval
Definition
Assumes equal intervals, but does not have absolute zero. Farenheit, Celcius
Term
Ratio
Definition
Assumes absolute zero. Numbers can be +, -, x, /.
Term
Measures of Central Tendency
Definition
Mode- most frequently occurring value
Median- the middle value
Mean - arithmetic average
Term
Measures of Variability
Definition
Describe how much dispersion or scatter there is in a set of data.
Term
Range
Definition
Distance between the highest and lowest value
Term
Semi-interquartile Range
Definition
1/2 of the interquartile range
Term
Interquartile Range
Definition
tops of 1st and 3rd quarters of a distribution. Range between Q1 and Q3 - middle 50% of the distribution
Term
Variance
Definition
The average of the sum of squares
Term
Standard Deviation
Definition
Square root of the variance. Provides a single value that represents individual differences in a data set.
Term
Importance of Variability
Definition
Without individual differences there would be no variability and test would be useless in helping us make determinations or decisions about people. The greater the amount of variability among individuals, the more accurately we can make distinctions that need to be made among them.
Variability provides a portion of test score interpretation.
Term
Standard Error of the Difference
Definition
Comparing the difference between individual scores.
Comparing two scores obtained by one person on two different PARTS of a test; comparing the scores of two different people on the same test.
Standard Error of the Difference is BIGGER than SEM for either individual score because it's affected by measurement error from BOTH scores.
Term
What is the Spearman-Brown Coefficient used to test?
Definition
Split-half reliability. Allows you to estimate the internal consistent reliability for the WHOLE test.
Term
Spearman-Brown (split-half reliability) steps
Definition
1. Divide the test into two equivalent halves
2. Compute a Pearson's R between the scores on the two halves of the test.
3. ADJUST the reliability coefficient using Spearman-Brown formula.
Rsb = 2rxy/1+rxy
Supporting users have an ad free experience!