PSYB01H3 Lecture Notes - Parametric Statistics, Chi-Squared Test, Nonparametric Statistics

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Published on 22 Sep 2012
School
UTSC
Department
Psychology
Course
PSYB01H3
Chapter 4- Conceptualization and Measurement
Measuring Mental Health and Mental Illness
being mentally healthy means u dunt have a diagnosable mental disorder or
disability
ohowever u may say it’s a mentally happy person is happy mm thriving
ect
oso how do u no which one it is and how develop constructs
Case study: Keyes (1997) - Is mental health than just lack of mental illness?
oRooted in positive psyc- argues that thers to mental health then simply
the absence of negatives
oLearn about the construct on the next slide cuz that’s wat the point
basically is
Developing and Defining Constructs
define ur ideas into a clearly defined theory- which provides the conceptual
framework for ur studies, meaning of terms and identifies how variable re to
measured and the rationale
Theoretical Constructs
theory unites concepts with the variables and measurements and it does this
by translating abstract concepts into a calculable variables which all have
objective measurement
abstract concepts are referred to as constructs
construct – specified in a theory in order to describe , explain and predict a
wide range of related empirical findings
Not directly observable Must be translated into an operational defn
Operational Defn of Constructs
operational defn-provides a recipe for spec variables that are to be used to
measure a construct
ooperational defn of a construct isn’t limited to spec how to measure it
oin lab studies it can spell out conditions under which the construct is
expected to occur – it can identify the independent variables that are
expected to prod the construct
eg construct of anxiety can be in 3 distinct variables—measures of
psycphysiology, obs ratings and self report rep 3 diff dependent variables of
the same construct,
if u have time read pgs 97-98
structure of a scientific theory begins with abstract constructs which in turn are
translated or operationalized into measurable independent and dependent
variables
sound prog of research depends on the extent to which these operations
capture the nature of the theoretical constructs under investigation
scientific validity of a theory or a theoretical construct hinges on the extent to
which it descries, predicts and explains those empirical relationships that are
uncovered between independent and dependent variables
many times the relationships between independent and dependent variables
will be linked , connected or mediated by intervening variables , hyp internal
states that are critical components of deductive struct of a theory
Building Constructs
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mental health vs mental illness ... keys adopted a conceptual framework
rooted in the school of psyc known as positive psyc
positive psyc- scientific study of ordinary human strengths and virtues seeks
to learn about human thriving , optimism , joy, capabilities
pgs 100-101
Measurement of Psyc Constructs
We investigate if our hyp constructs reflect objective reality through
measurement?
oanswer is to find the correct objective reality we use a lot of methods
measurement - Assignment of numerals to variables according to some
objective rule
oSo then u can use #s instead of just names
use multiple methods of measurement is essential
oessential for use to develop a complete understanding of a phenomenon
and its relationships
odiif forms of measurement for the same construct allow understanding
Levels of measurement
measurement : process by which #s are used to designate objects or events
according to some objective rule
rule- means the way #s are used to rep a particular scale of measurement
ocan have 1 of 4 scales which range in complexity nominal( least
complex) , ordinal, interval and ratio( most complex)
nominal ( also called categorical or qualitative level) – identifies variables
whose values have no mathematical interpretation they vary in kind or
quality but not amount
ovariables values are mutually exclusive- of every case can only have one
value
ovariables values are exhaustive when every case can be classified into
one of the categories
owhen variables are mutually exclusive and 0065haustive- every case
corresponds to 1 attribute ( value )
Special case of dichotomies- variables have 2 values but still measured at
the nominal level
ordinal level of measurement – 1st of 3 quantitative labels – the #s assigned
to response choices allow for greater than and less than distinctions
ocuz it allows for ranking it’s also referred to as ranking scale
oDoes not assume equal distance between values
olikert scale is common metric system , 1- none of the time , 2 a little of
the time , 3 some of the time , 4 most of the time , 5 all of the time
interval – has all characteristics of nominal and ordinal scales of measurement
oit gives a name or category for each obs with the # serving as a code for
the able
olike ordinal the responses are numerically ordered or ranked form lowest
to est on the same characteristic
oEqual distances between values and No true zero point
ou can’t say 80 C is twice as much as 40
Ratio level – the #s rep fixed measuring units and an absolute zero point ( 0
means absolutely no amount of whatever the variable indicates )
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Document Summary

Developing and defining constructs: define ur ideas into a clearly defined theory- which provides the conceptual framework for ur studies, meaning of terms and identifies how variable re to measured and the rationale. Important when considering statistical analyses: non-parametric statistics = test hyp for variables that use nominal and ordinal scales, eg chi square test, parametric statistics = generally used with variables that are measured on either interval and ratio scales. Measurement reliability: test-retest reliability= scores should remain consistent over time. Interobserver reliability= degree to which raters code the same observed behavior. Logic of measurement validity: circular reasoning use of independent measures of theoretically liked outcomes to validate the assessment protocol effectively avoids a common pitfall in research design, research design can be invalidated by circular reasoning. Content validity: valid test needs to provide full measure of a construct, content validity- refers to extent to which the test items have sufficient breadth to capture the full range of a construct.

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