MAR 4613 Exam 2 (Ch. 9 &12)

Systemic Sampling Error

- error results from nonsampling factors, primarily the nature of a study's design and the correctness of execution. -It is not due to chance fluctuation.

What are extraneous variables that affect internal validity?

- history -mortality -selection -instrumentation -testing -maturation

Instrumentation Effect

-A change in the wording of questions, a change in interviewers, or a change in other procedures causes a change in the dependent variable.

Sampling Frame

-A list of elements from which a sample may be drawn; also called working population.

Testing Effect

-A nuisance effect occurring when the initial measurement or test alerts or primes subjects in a way that affects their response to the experimental treatments.

Snowball sampling

-A sampling procedure in which initial respondents are selected by probability methods and additional respondents are obtained from information provided by the initial respondents.

Proability Sampling

-A sampling technique in which every member of the population has a known, nonzero probability of selection.

nonprobability sampling

-A sampling technique in which units of the sample are selected on the basis of personal judgment or convenience. -The probability of any particular member of the population being chosen is unknown.

Sampling Unit

-A single element or group of elements subject to selection in the sample.

Laboratory Experiment

-A situation in which the researcher has more complete control over the research setting and extraneous variables.

Systemic Sampling

-A starting point is selected by a random process and then every nth number on the list is selected.

Primary Sampling Unit (PSO)

-A unit selected in the first stage of sampling.

Manipulation Checks

-A validity test of an experimental manipulation to make sure that the manipulation does produce differences in the independent variable.

Judgement (Purposive) Sampling

-An experienced individual selects the sample based on personal judgment about some appropriate characteristic of the sample member.

Demand Characterisitics

-An experimental design element or procedure that unintentionally provides subjects with hints about the research hypothesis.

Census

-An investigation of all the individual elements that make up a population.

Population (universe)

-Any complete group of entities that share some common set of characteristics.

Simple random sampling

-Assures each element in the population of an equal chance of being included in the sample

Interaction Effect

-Differences in dependent variable means due to a specific combination of independent variables.

Between-Subject Design

-Each subject receives only one treatment combination. -Usually advantageous although they are usually more costly. -Validity is usually higher.

Maturation Effect

-Effects that are a function of time and the naturally occurring events that coincide with growth and experience.

Quota Sampling

-Ensures that various subgroups of a population will be represented on pertinent characteristics to the exact extent that the investigator desires.

Within-Subject design

-Involves repeated measures because with each treatment the same subject is measured.

Convenience Sampling

-Obtaining those people or units that are most conveniently available.

Sampling Frame Error

-Occurs when certain sample elements are not listed or are not accurately represented in a sampling frame.

Demand Effect

-Occurs when demand characteristics actually affect the dependent variable.

Mortality Effect (Sample Attrition)

-Occurs when some subjects withdraw from the experiment before it is completed.

Experimental Conditions

-One of the possible levels of an experimental (independent) variable manipulation. -Variables included in the statistical analysis as a way of controlling or accounting for variance due to that variable:

How to renounce demand effects?

-One treatment/ Subject - Use a disguise - Use a blind administrator - Isolate Subjects

Hawthorne Effect

-People will perform differently from normal when they know they are experimental subjects.

Why sample?

-Pragmatic reasons -Accurate and reliable results -Destruction of test units

Field Experiment

-Research projects involving experimental manipulations that are implemented in a natural environment.

What are the sources of experimental confound?

-Sampling error -Systematic error -Later-identified extraneous variables

Manipulation of the Independent Variable

-Several experimental treatment levels (different values of the independent) may be used. -More than one independent variable may be examined.

advantages of quota sampling

-Speed of data collection -Lower costs -Convenience

External validity

-The accuracy with which experimental results can be generalized beyond the experimental subjects.

Main Effect

-The experimental difference in dependent variable means between the different levels of any single experimental variable.

Internal Validity

-The extent that an experimental variable is truly responsible for any variance in the dependent variable.

proportional stratified sample

-The number of sampling units drawn from each stratum is in proportion to the population size of that stratum.

disproportional stratified sampling

-The sample size for each stratum is allocated according to analytical considerations.

Selection

-The selection effect is a sample bias that results from differential selection of respondents for the comparison groups, or a sample selection error.

Basic experimental design

-a single independent variable and a single dependent variable.

Factorial Experimental Design

-allows for an investigation of the interaction to two or more independent variables.

Types of Nonprobability Samples

-convenience -judgment (purposive) - quota

what are some ethical issues in experimentation

-debriefing experimental subjects -attempts to interfere with a competitiors' test-marketing efforts

Characteristics of field experiments

-high realism (natural) - many extraneous variables - low control -high cost -long duration - subjects unaware of participation

Characteristics of lab experiments

-low realism (artificial) - few extraneous variables -high control - low cost -short duration -subjects are aware of participation

Possible sources of bias in nonprobability sampling

-similar to interviewer -easily found -willing to be interviewed -middle-class

Types of probability sampling

-simple random -systemic -stratified

Test Units

-the subjects or entities whose responses to treatment are measured or observed.

Experimental Treatment

-the way an experimental variable is manipulated.

Stages in the selection of a sample

1. Define the target population 2. Select a sampling frame 3. Determine if a probability or non-probability sampling method will be chosen 4. Plan procedure for selecting sampling units 5. Determine sample size 6. Select actual sampling units 7. Conduct fieldwork

Cohort Effect

A change in the dependent variable that occurs because members of one experimental group experienced different historical situations than members of other experimental groups.

Reverse Directory

A directory similar to a telephone directory except that listings are by city and street address or by phone number rather than alphabetical by last name.

Sample

A subset, or some part, of a larger population

Secondary Sampling Unit

A unit selected in the second stage of sampling.

Tertiary Sampling Unit

A unit selected in the third stage of sampling.

Population element

An individual member of a population

International Research

Availability of sampling frames varies dramatically around the world.

How to establish control in experimental design?

Constancy of conditions and Counterbalancing

Online Panels

Lists of respondents who have agreed to participate in marketing research along with the e-mail contact information for these individuals

Stratified Sampling

- Simple random subsamples that are more or less equal on some characteristic are drawn from within each stratum of the population.

History Effect

Occurs when some change other than the experimental treatment occurs during the course of an experiment that affects the dependent variable.

example of history effect

a major employer closes its plant in a test market area

example of testing effect

a questionnaire about the traditional role of women triggers enhanced awareness of females in an experiment

In which experimental research design does each subject receive only one treatment combination

between-subject design

Covariate

continuous variable

example of selection effect

control group and experimental group is self-selected group based on preference for soft drinks

Categorical variables

described by class or quality

Continuous Variables

described by quantity (level)

example of between-subject design

each subject is measured only once after being exposed to only one color lighting combination

The group receiving the treatment being studied is called the ___

experimental group

Research projects involving experimental manipulations that are implemented in a natural environment are called ___?

field experiments

Example of within-subject design

same subject is measure after being exposed to each color lighting combination

Cell

specific treatment combination associated with an experimental group

A researcher is conducting experiment in which one group of people is exposed to one advertisement and another group is exposed to another advertisement. Specifically, he is examining the effect of headline font size on consumers' attitude toward the brand advertised. The participants in this experimental research are referred to as ___

subjects

example of maturation effect

subjects become tired during the experiment

example of mortality effect

subjects in one group of a hair dying study marry rich widows and move to florida

Experimental Group

•A group of subjects to whom an experimental treatment is administered.

Control Group

•A group of subjects to whom no experimental treatment is administered.

Counterbalancing

•Attempts to eliminate the confounding effects of order of presentation by varying the order of presentation (exposure) of treatments to subject groups.

How to overcome sampling errors?

•Randomization •Matching •Repeated measures •Control over extraneous variables

What are examples of systemic or nonsampling error?

•Subject selection, experimental design, and unrecognized extraneous variables

Constancy of Conditions

•Subjects in all experimental groups are exposed to identical conditions except for the differing experimental treatments.

Experimental Confound

•When there is an alternative explanation beyond the experimental variables for any observed differences in the dependent variable.

Sampling services (list brokers)

Provide lists or databases of the names, addresses, phone numbers, and e-mail addresses of specific populations.

-Artificial laboratory experiments usually are high in internal validity, while naturalistic field experiments generally have less internal validity, but greater external validity.

TRUE

Field Experiments have a more natural environmental setting

TRUE

Lab experiments have a more artificial environmental setting

TRUE

Once a potential confound is identified, the validity of the experiment is severely questioned

TRUE

Selecting dependent variables that are relevant and truly represent an outcome of interest is crucial.

TRUE

Random Sampling error

The difference between the sample result and the result of a census conducted using identical procedures. - A statistical fluctuation that occurs because of chance variations in the elements selected for a sample.

Subjects

The sampling units for an experiment, usually human respondents who provide measures based on the experimental manipulation.

Blocking Variables

categorical variables

According to an academic study published here, products from less developed countries received lower consumer evaluations than those from industrialized countries under all tested conditions. Additional results from the study also indicate that a product's brand name changes the effect of country of origin on consumer evaluations so that a famous brand erases such differing effect of country of origin on consumer product evals. the additional results illustrate a(n) ____/

interaction

the question as to whether the independent variable was the sole cause of the change in the dependent variable is the basic issue in ___

internal validity

Despite positive results, some scientists turn somewhat skeptical about the results as many patients can recover from COVID probably without Remdesivir. If it were a field experiment, what kind of extraneous variables is the key reason for their skepticism given the possibility of those patients recovering by themselves?

maturation effect

salespeople are tested one year after a sales training program and perform better on the exam, not because of the training program but because they have gained one year's experience in sales. What type of effect has occurred?

maturation effect

when some subjects stop participating in an experiment before it is completed, affecting the results of the study, a(n) ___ effect has occured

mortality

example of instrument effect

new questions about women are interpreted differently from earlier questions