Module 6 drop box Module 6 Quantitative Research Strategies Descriptive Research Module 6 covers an extensive amount of information related to descripti

Module 6 drop box Module 6

Quantitative Research Strategies

Descriptive Research

Module 6 covers an extensive amount of information related to descriptive research.  For the purpose of this assignment, we will focus on the concept of “sampling.”  Respond to the following scenario:

You are a researcher who wants to obtain a simple random sample of 1,000 members of the American Medical Association to whom you will send a questionnaire about their views concerning the appropriate training for Licensed Practical Nurses. List the steps you would take in selecting your sample.

Your submission of this assignment will likely consist of only one page.  Use the same formatting described in Week 1. Use a 12 pt. Times New Roman font. QUANTITATIVE RESEARCH

METHODOLOGIES

Descriptive Research Chapter Eight

What is Descriptive Quantitative

Research?

 This general category of research designs involves

either identifying the characteristics of an observed

phenomenon or exploring the possible associations

among two or more phenomena.

 In every case, descriptive research examines a

situation as it is.

Descriptive Research Designs

All of these

studies yield

quantitative

information

that can be

summarized

through

statistical

analyses.

 Observation Studies

 Correlational Research

 Developmental Designs

 Survey Research

Observation Studies

 In quantitative research, observation studies are
different than observations in qualitative research

 An observation study does not necessarily involve
members of the animal kingdom

 A quantified observation study tends to have a
particular, pre specified focus

 When humans are the object, the behavior is quantified
in some way – behavior may be counted to determine
its overall frequency

 In some situations, behavior is rated

 The researcher strives to be as objective as possible

Observation Studies

 Strategies to maintain objectivity:

 Define the behavior precisely and concretely

 Divide the observation period into small segments

 Use a rating scale to evaluate the behavior

 Have two or three people rate the same behavior

independently

 Train the rater(s) to use specific criteria when counting

or evaluating

Correlational Research

 A correlational study examines the extent to which
differences in one characteristic or variable are
related to differences in one or more other
variables

 A correlation exists if, when one variable increases,
another variable increases or decreases in a
somewhat predictable fashion

 Researchers gather data about two or more
characteristics for a particular group of people or
other appropriate units of study

Correlational Research

 Whatever the nature of the data, at least two different
characteristics are measured in order to determine
whether and in what way these characteristics are
interrelated

 A scatter plot may be used to allow a visual inspection
of the relationship between two variables

 The scatter plot allows us to describe the homogeneity or
heterogeneity of variables

 It also allows us to describe the degree to which the two
variables are intercorrelated, perhaps by computing a
statistic known as a correlation coefficient

 It allows us to interpret data and give them meaning

Correlational Data – Caution

 In all correlational studies, be alert for faulty logic

 We can never infer a cause-and-effect relationship on
the basis of correlation alone

 Correlation does not, in and of itself, indicate
causation

 A way to explore the dynamics beneath the correlation
is through a statistical procedure called structural
equation modeling (SEM)

 Another way is to follow up a correlational study with
one or more experimental studies to test various
hypotheses about what causes what

Developmental Designs

 There are two types of Developmental Designs

 A cross-sectional study, wherein people from several

different age-groups are sampled and compared

 A longitudinal study, wherein a single group of people

is followed over the course of several months or years,

and data related to the characteristic(s) under

investigation are collected at various times

Developmental Designs

 When longitudinal studies are also correlational studies,
they enable researchers to identify potential mediating
and moderating variables in correlational relationships

 A mediating variable (intervening variable) may help
explain why a characteristic is correlated with another
characteristic

 A moderating variable influences the nature and strength of
a correlational relationship

 A statistical analysis such as structural equation modeling
(SEM) can be helpful for identifying mediating and
moderating variables in a longitudinal study

 Correlational studies cannot conclusively demonstrate
cause-and-effect relationships

Developmental Designs

 Cross-sectional studies are easier and more

expedient to conduct than longitudinal studies

because the researcher can collect all the needed

data at a single time

 Disadvantages of cross-sectional studies

 Different age groups sampled may have been raised

under different environmental conditions

 We cannot compute correlations between

characteristics at different age levels

Developmental Designs

 To address some of the weaknesses of longitudinal

and cross-sectional designs, researchers occasionally

combine both approaches in what is known as a

cohort-sequential study

 Cross-sectional, longitudinal, and cohort-sequential

designs are used in a variety of disciplines, but are

most commonly seen in developmental research

studies

Survey Research

 Survey research involves acquiring information

about one or more groups of people by asking

them questions and tabulating their answers

 The ultimate goal is to learn about a large

population by surveying a sample of that

population; thus, this approach might be called a

descriptive survey or normative survey

Survey Research

 A survey is simple in design; however, survey design

makes critical demands on the researcher

 Survey research

 Captures a moment in time

 Relies on self-reporting of data (by individuals)

 May employ

 Face-to-face interviews

 Telephone interviews

 Written questionnaire

Planning for Data Collection in a

Descriptive Study

 In quantitative research, a descriptive study

invariable involves measuring one or more variables

in some way

 Consider the distinction between substantial and

insubstantial phenomena

 Many descriptive studies address complex variables

using a variety of strategies

 Checklist

 Rating scale/Likert scale

Choosing a Sample in a Descriptive

Study

 A researcher will usually not study an entire

population – instead, he or she will select a subset,

or sample, of the population

 The researcher can use the results obtained from the

sample to make generalizations about the entire

population only if the sample is truly representative

of the population

Sampling Designs

Two

categories of

sampling:

Probability

Sampling and

Non-

Probability

Sampling

 Probability sampling

Simple random sampling

Stratified random sampling

Proportional stratified sampling

Cluster sampling

Systematic sampling

Sampling Designs

Two

categories of

sampling:

Probability

Sampling and

Non

Probability

Sampling

 Nonprobability Sampling

 Quota sampling

 Purposive sampling

Sampling Surveys of Large Populations

 The sample must be representative of the

population about which inferences are to be made

 Random does not mean haphazard

Identifying a Sufficient Sample Size

 The larger the sample size, the better

 The sample size is referred to by the symbol N

 Guidelines

 For smaller populations, say, N=100 or fewer, survey

the entire population

 If N is around 500, 50% should be sampled

 If N is around 1500, 20% should be sampled

 If N=5000, a sample size of 100 should be adequate

Bias in Research Sampling

 Bias is any influence, condition, or set of conditions

that singly or in combination distort the data

 Bias attacks the integrity of the facts

 Report response rate

Acknowledging the Probable Presence

of Bias

 When formulating conclusions about the data, a

researcher must be sure to consider the effect that

bias may have had in distorting the data

Interpreting Data in Descriptive

Research

 There is more to research than data collection

 All research activity is subordinate to the research

problem itself

 Two basic principles of research

 Seek the answer to a problem in light of the data that

relate to the problem

 Interpretation of the data is all-important