Ch. 7 Flashcards
Scales of Measurement:
Nominal Scale, Ordinal Scale, Interval Scale, Ratio Scale, Itemized-Ratings Scale, Graphic- Ratings Scales, Comparative-Ratings Scale
Measurement-
Rules for assigning numbers to objects to represent quantities of attrubutes.
Nominal Scale-
Measurement in which numbers are assigned to objects or classes of objects solely for the purpose of identification. Uniquely identify indivuduals.
Ordinal Scale-
Measurement in which numbers are assigned to data on the basis of some order. (ex. more than, greater than) or the objects.
Interval Scales-
Measurement in which the assigned numbers legitimately allow the comparison of the size of the differences among and between members.
Ratio Scale-
possesses a natural, or absolute, zero that reflects the complete absence of the attribute being assessed.
Measuring Attitudes and other unobservable concepts:
Self-Reports, Itemized-ratings scales, Summated-rating scale, semantic-differential scale, snake diagram, Graphic-rating scales, Comparactive-ratings scales, constant-sum methods.
self-reports-
A method of assessing attitudes in which individuals are asked direcly for their beliefs about or feelings toward an object or class of objects.
Itemized-Ratings Scale-
A scale on which individuals must indicate their ratings of an attribute or object by selecting the response category that best describes their position on the attribute or object. 5 to 9 categories work the best.
Summated-ratings scale- (Likert scale)
A self-report technique for attitude measurement in which respondents indiccate their degree of agreementor disagreement with each of a number of statements.
Semantic-Differential Scale-
A self-report technique for attitude measurement in which respondents are asked to check which cell between a set of bipolar adjectives or phrases best describes their feelings toward the object.
Snake Diagram-
A diagram that connects the average responses to a series of semantic-differential statements, thereby depicting the profile of the object or objects being evaluated.
Graphic-Ratings Scales-
A scale in which individuals indivate their ratingsof an attribute typically by placing a check at the appropriate point on a line that runs from one extreme of the attribute typically by placing a check at the appropraite point on a line that runs from one extreme to the other.
Comparative-ratings scales-
A scale requiring subjects to make their ratings as a series of relative judgements or comparisons rather than as independent assessments.
Constant-sum method-
A comparactive-rating scale in which an individuela diviedes some given sum amoung two or more attributes on a basis such as importance or favorability.
Number of items in a scale-
- Global measure- A measure designed to provide an overall assessment of an object or phenomenon, typically using one or two items.
- composite measures- A measure designed to provide a comprehensixe assessment of an object or phenomenon, with items to assess all relevant aspects or dimensions.
Different Validity and Reliabiltiy of measures:
Systematic error, random error, validity, and reliability.
Systematic Error-
Error in measurement that is also known as constant error because it affects the measurement in a constant way.
Random Error-
Error in measurement due to temporary aspects of the person or measurement situation and which affects the measurement in irregular ways.
Validity-
Differences in scores on a measuring instrucment reflect true differences amoung individuals, groups, or situations in the characteristic that it seeks to measure, or true differneces in the same indivual, group, or situation from one occasion, to another, rather than systematic or random errors.
Reliabilty-
Ability of a measure to obtain similar scores for the same object, trait, or construct accross time, across different evaluations, or across the items forming the measure.
