Basic Terms

consistently gives the same answer

• measures what it is supposed to measure
• accuracy 

the study really investigates the proposed question

how well the study results are generalized across populations, settings and time

entire group or class of subjects, variables, concepts, or phenomena

process of examining every member of a population

a subset that is taken to be representative of the entire population

• selected according to mathematical guidelines whereby the chance for selection of each unit is known
• quantitative

• selected for convenience of the researcher
• qualitative research

• available sample
• ex. group of students in mass media

individuals are not selected mathematically

subjects selected on basis of specific characteristics

subjects selected tot meet a predetermined or known percentage

ex. survey composed of 10% VCR owners and 90% non-VCR owners reflects the population characteristics

based on other sample member's referrals

each subject in pop has an equal chance of selectoin

ex. reading table of numbers

every nth subject is selected from a population

ex. blocks of 4 people and then every third person within that block

complete list of members in the pop of sample

the order of the items in the pop list may bias selection

ex. every 10th tv program from a list may be an ABC program

used to guarantee a subsample of the population is represented; homogenous

ex. graduate students out of all students

sample size: the ______, the better

predictor variables

criterion variables

• specifies procedures to be followed in measuring a concept; clear statement about what is to be observed
• how the variable is measured

ex. go to the grocery store and see sign for milk; go to sign and what's underneath it is milk

defines a construct using other constructs (like a dictionary)

a term that expresses an abstract idea formed by generalizing from particulars and summarizing related observations.

ex. table” – concept that represents a wide variety of observable objects, ranging from a plank supported by concrete blocks to a piece of furniture commonly found in dining rooms.“emo”“Taffies” – technologically advanced families

can take on any value, including fractions; can be meaningfully broken into smaller subsections

ex. height (can distinguish between 72.12 inches tall and 72.13 inches tall); time spent watching television (person A spent 3.12 hours watching while person B spent 3.13 hours); the average number of children in a family

includes only a finite set of values; cannot be divided into subparts

number of children in family (bc the unit is a person); political affiliation; gender of a person; population

numerals or other symbols are used to classify people, objects, or characteristics; labels that stand for the respective categories, have no significance

rocks can be classified into 3 categories: igneous, sedimentary, metamorphic. A scientist who assigns a 1 to igneous, a 2 to sedimentary, and a 3 to metamorphic has created a nominal scale

• ranked along some dimension, such as from smallest to largest;
• numbers generally have some mathematical meaning;
• equivalence – all in one category are treated equally

ex.  “socioeconomic status” – categorizing families according to class: lower, lower middle, middle, upper middle, upper

• has all the properties of an ordinal scale and the intervals between adjacent points on the scale are of equal value;
• property of equal differences
• no true zero (can't have it)

ex. temperature – the same amount of heat is required to warm and object from 30 to 40 degrees as to warm it from 50 to 60 degrees.

• interval properties
• has true zero

Time spent watching TV or number of words per story

methods of data collection including focus groups, field observation, in-depth interviews, case studies, etc

• variables under consideration must be measured
• large samples often used to generalize results

uses interval measurement for scale in which respondents strongly agree, agree, are neutral, disagree, or strongly disagree with the statements

uses interval measurement for scale consisting of 7 spaces between two bipolar adjectives (good___bad), asked to choose where his or her position lies