week 3 Flashcards
Define a construct
are hypothetical attributes or mechanisms that help explain and predict behavior in a theory
can not directly observed or measured , it is possible to observe and measure the behaviors associated with the construct
Define a variable
characteristics or conditions that change or have different values for different individuals
Identify examples of well defined and easily measured variables
to evaluate difference or changes in variables it is essential that we are able to measure them
easily measured variables: age, weight, height
abstract: intelligence
Identify examples of variables are abstract
anxiety, intelligence
Briefly explain what an operational definition is and why operational definitions are sometimes necessary.
is a procedure for measuring and defining a variable that cannot be observed or measured directly
necessary to convert an abstract variable into a concrete entity in order to be observed and studied
operationally define Receptive vocabulary
Number of words recognized upon seeing them.
Ability to follow commands
Answer simple complex yes/no questions.
Open-ended questions after being read a story.
Ability to point to correct objects or pictures given an auditory command.
operationally define expressive vocabulary
Count the amount of words spoken.
looking at a picture and describing what they see
Use a battery of expressive language assessments such as clinical evaluation of language fundamentals three, which measures phonological awareness, sentence structure, language content and memory, etc.
operationally define Hoarseness
Clinician rating of hoarseness.
volume and pitch
vocal rating scale
operationally define breathiness
Clinician rating
vocal rating scale
[type of validity] is demonstrated when scores obtained from a new measure are directly related to scores obtained from an established measure of the same variable.
concurrent validity
[type of validity] is demonstrated when scores obtained from a measure accurately predict behavior according to a theory.
predictive validity
[type of validity] requires that the scores obtained from a measurement procedure behave exactly the same as the variable itself. This type of validity is based on many research studies that use the same measurement procedure and grows gradually as each new study contributes more evidence.
construct validity
Define test-retest reliability
is established by comparing the scores obtained from two successive measurements of the same individuals and calculating a correlation between the two sets of scores
Define inter-rater reliability
is a degree of agreement between two observers who simultaneously record measurements of behaviors
used when measurements are obtained by direct observation of behaviors
can be measured by computing the correlation between the score from the two observers
What is a ceiling effect, and how can it be a problem?
ceiling effect is a sensitivity problem where the score obtained in a research study tend to cluster at one end of the measurement scale. For ceiling effect the range is restricted at the high end - it can’t go any higher
What are demand characteristics, and how do they limit the validity of the measurements obtained in a research study?
demand characteristics refers to any of the potential cues or features of a study that 1) suggest to the participants what the purpose and hypothesis is and 2)influence the participants to respond or behave in a certain way
might limit the validity because participants who are aware they are being observed and measured may react in unpredictable or unnaturally thereby influencing the measurements they produce
What is a population?
the larger group of interest. although the entire populaion usually does not partiicpate in a resaerch study the results from the study are gnerlaized to the entire population
A speech-language pathologist has developed a new test for measuring receptive language and would like to determine the validity of the test. The new test and an established measure of receptive language are both administered to a sample of participants. Describe the pattern of results that would establish concurrent validity for the new test.
first must identify if the test is accurately measuring an individual’s receptive language ability
should compare the new test results with another test that is already used in the field to establish the accuracy/validity of the new test
identify the correlation of results between two tests: if positive, negative, or no correlation
What are the four scales of measurement? Identify examples of each.
nominal – qualitative variables (gender, country, hair color)
ordinal – different names but organized sequentially (ranked data, educational level)
interval – organized sequentially, all intervals are same size, arbitrary 0 point (temperature in Fahrenheit)
ratio - organized sequentially, all intervals are same size, has true 0 point (# of stuttered syllables in 5 min conversation)
Under what circumstances can a sample be biased?
selection bias occurs when participants or subjects are selected in a manner that increases the probability of obtaining a biased sample
a biased sample is a sample with different characteristics from those of the population
identify the five research designs
descriptive, correlational, experimental, quasi-experimental, and nonexperimental
name the broad research design category: Designs that examine individual variables (instead of relationships between variables)
descriptive research strategy: describes current state
name the broad research design category: Designs that examine relationships between variables by measuring two (or more) variables for each participant
correlational: relationships between 2 variables (linear, curvilinear, positive, negative)
No causation
How does x compare to y
Good external validity
Low internal validity because can’t control
name the broad research design category: Designs that examine relationships between variables by comparing two (or more) groups/sets of scores.
Experimental - highest level of research evidence; establishes causation using strict controls
quasi-experimental - can draw causation; less control than experimental like no randomization
Non experimental - looks at preexisting data, produces a description of the relationship b/w 2 variables but not causation
Experimental research studies tend to have very (high/low) internal validity but often have relatively (high/low) external validity.
Experimental research studies tend to have very LOW internal validity but often have relatively HIGH external validity.
Experimental research studies tend to have very HIGH internal validity but often have relatively LOW external validity.
Under what circumstances can a sample be biased?
selection bias occurs when participants or subjects are selected in a manner that increases the probability of obtaining a biased sample
a biased sample is a sample with different characteristics from those of the population
usually n = 30, larger sample more representative
selection bias
what is the accessible population
a portion of the target population consisting of individuals who are accessible to be recruited as partipcants in the study
what is a correlational research strategy
examines the relationship between 2 variables as they exist naturally for a set of indiivudals
does not try to explain relationship between the 2 variables –> no cause and effect
a research study that simply measures two variables for each individual and produces the kind of data in which each variable is measured with numerical scores
what is an experimental research strategy
is intended to answer cause and effect questions about the relationship between two variables
what is a quasi-experiemtnal research strategy
quasi-experimental: attempts to answer cause-effect but not as rigorously controlled
Describe the concept of a study’s internal validity
a research study has internal validity if it produces a single unambiguous explanation for the relationship between two variables
What are the common threats to internal validity?
is any factors that allows for an alternative explanation; any factors that generate doubts about the accuracy of the results or raises questions about the interpretation of the results
-environmental variables
-individual differences: characteristics differ from one person to another
-time-related variables:
history
maturation – occurs over time/longitudinal
instrumentation
testing effects: fatigue, carry-over effects
regression to the mean: the more you take a test, the more it will hover around the true score
Describe the concept of a study’s external validity
refers to the extent to which we can generalize the results of a research study to people, settings, times, measures and characteristics other than those used in that study
What are the common threats to external validity?
is any characteristic of a study that limits the ability to generalize the results from a research study
threats include –
generalization from a sample to the general population
- selection bias
- volunteer bias
generalization from one research study to another
- novelty effect – reactions can vary
- experimenter characteristics
generalization from a research study to a real world situation
- generalizability across measurements
what is the goal of a research study?
is to measure a sample and then generalize the results to the population
Experimental research studies tend to have very (high/low) internal validity but often have relatively (high/low) external validity.
what is a correlational research strategy
examines the relationship between 2 variables as they exist naturally for a set of individuals
does not try to explain relationship between the 2 variables
Relationships between 2 variables (linear, curvilinear, positive, negative)
Good external validity
Low internal validity because can’t control
what is nonexperimental research strategy
is intended to demonstrate a relationship between variables but it does not attempt to explain the relationship or establish causation
Looks at preexisting data
what is a descriptive research strategy
is intended to answer questions about the current state of individual variables for a specific group of individuals
Example type: case study
Weak internal validity - no control because looking at how something exists
Weak external - not enough to generalize
which 3 research strategies involve comparing groups of scores
experimental, quasi experimental, non experimental
what is validity of measurement and what is validity of a reasearch study
validity of a measurement is refers to whether the procedure actually measures the variable that is claims to measure
validity of a research study refers to the quality of the research process and the accuracy of the results
what is validity of measurement and what is validity of a reasearch study
validity of a measurement is refers to whether the procedure actually measures the variable that is claims to measure
validity of a research study refers to the quality of the research process and the accuracy of the results
what is a confounding variable
is an extraneous variable that changes systematically along with the two variables being studies
the key to achieving internal validity is to ensure that no extraneous variable is allowed to become a confounding variable
what is a confounding variable
is an extraneous variable that changes systematically along with the two variables being studies
- enviromental variables
- individual differences
- time-related variables
the key to achieving internal validity is to ensure that no extraneous variable is allowed to become a confounding variable
Compare and contrast interval and ratio scales.
ratio has a true zero
temperature in C or F is interval because 0 is not the lowest point whereas temp in Kelvin is ratio bc 0 is the lowest possible
What are the defining characteristics of a between-subjects design as compared to a within-subjects design?
between-subjects: compares scores different groups
within-subjects: compares scores in two or more tx conditions by observing the same individual in each condition
Explain the general advantages and disadvantages of a within-subjects design.
advantages:
requires fewer participants
eliminates/reduces individual difference confounding bc it’s the same participant
disadvantages:
performance is susceptible to time-related factors
fatigue, sentimental changes btwn conditions, practice affects, attrition
What are the two measures of variability?
variance: average squared distance of scores from mean
standard deviation: avg distance of scores from mean
easier to interpret bc in same units of measure
