Inferential statistics
Communication media researchAmong the research can be conducted
on mass media include:* Research in the print media* Research in
the electronic media* Research in media effects* Research in
information and communication technology (ICT) and cyber
communicationResearch in the print mediaFor newspapers and
magazinesA) READERSHIP RESEARCH: to know who reads the media in
terms of their profile and likeness of the media, specifically
there are five types of studies:1) Reader profile provide a
demographic summary of the readers of a particular publication.
Recently psychographic studies and lifestyle segmentation research
are conducted to more about readers2) Item-selection studies to
determine who reads specific parts of the publication3) Reader
nonreader studies to find out who reads the newspapers and who does
not read and their reasons for reading or not reading a particular
newspapers4) Uses and gratification studies to study all media
content. For newspapers it is used to determine the motives that
lead to newspaper reading and the personal and psychological
rewards that result from it5) Editor-reader comparisons to see
whether there is any correspondence between the two groups6)
Magazine readership research similar to research conducted for
newspapers, but differ in terms of particulars such as this
research asks readers to rate each article on a four point scale of
read all, read most, read some and didnt readB) CIRCULATION
RESEARCH: to measure circulation in terms of the overall
characteristics of a particular market, or the circulation pattern
of a magazine among certain demographic groups or in specific
geographic areas. Also, to identify other market level or market
structure variables that have an impact on circulationC) NEWSPAPER
MANAGEMENT RESEARCH: conducted to evaluate business expansion, job
requirement, technology advancement and to fulfill the new
competitive environmentD) TYPOGRAPHY AND MAKEUP RESEARCH: measures
the effects of news design elements with regards to typeface and
page makeup on readership, reader preference, and comprehensionE)
READABILITY RESEARCH: to measure the extent which readers
understand the piece, are able to read it at an optimal speed, and
find it interestingResearch in the electronic mediaFor television
and radio mostly involving rating research - information about
audience size- important for advertisers in determining advertising
rates- Nielsen Media Research is the main player in rating research
internationallyResearch that does not involve rating include: -
Market study- Format study- Program element importance- Station
image- Personality (talent) studies- Advertiser (account) analysis-
Account executive research- Sales research- Diversification
analyses Research in media effectsSix major areas of media effect
research:- Antisocial and prosocial effects of media contents- Uses
and gratifications- Agenda setting by the media- Cultivation of
perceptions of social reality- Advertising and the socialization of
children- Campaign assessment researchAntisocial and prosocial
effects of media contents the social impact of mass communication
towards society as a result of watching movies and television. The
study includes information gain, attitude change and influence on
behavior, especially on childrenUses and gratifications takes the
view of media consumers as it examines how people use the media and
the gratifications they seek and receive from their media
behaviors. Researchers assumes that audience members are aware of
and can articulate their reasons for consuming various media
content Agenda setting by the media it proposes that the public
agenda, the kinds of things people discuss, think and worry about
is powerfully shaped and directed by what news media choose to
publicize. Agenda setting research examines the relationship
between media priorities and audience priorities concerning the
relative importance of news topics Cultivation of perceptions of
social reality the basic assumption is that repeated exposures to
consistent media portrayals and themes will influence the public
perceptions of these items in the direction of the media
portrayalsAdvertising and the socialization of children to
determine comprehensibility and persuasiveness of the children that
are exposed to commercials. Done to develop theory concerning
children and consumer socialization, and guideline for public
policy Campaign assessment research to gauge the reach of specific
campaign message among targeted audience and its impact in terms of
knowledge gained, attitude change and behavior modification
Research in ICT and cyber communicationAssessing the influence
and impact of information and communication technology (ICT)
towards society:- how the ICT has influence lifestyles?- study and
work environments- social communications- economic activities- how
it has effected the children, women and health?- getting and
sharing information- ethics among users etc. Doing
citation/quotationRefer to American Psychological Association (APA
style)The followings are guidelines in doing citation and quotation
in literature reviews according to scientific method1. State the
name of author with year in the citation. Names cited must be
listed in the reference list13- State the family name without
initial of the first and middle name- If there are three authors,
their names should be stated. If more than three, write the name of
first author followed by et. al. - For direct quotation as a whole,
the name of the author can be stated at the beginning or at the end
of quotation 14Example:Musa Abu Hassan (2008) mendapati media
sosial amat mempunyai pengaruh yang kuat dalam kalangan remaja masa
kini.orMedia sosial amat mempunyai pengaruh yang kuat dalam
kalangan remaja masa kini (Musa Abu Hassan, 2008).For direct
quotation of less than 40 words, it can be written in the sentence.
Example::Musa Abu Hassan (2002) menyatakan keinginan manusia untuk
berkomunikasi dengan cepat, cekap dan berkesan telah menjana
teknologi baru yang membolehkan mereka melakukan pelbagai perkara
termasuk yang tidak sepatutnya dilakukan. (p. 10)
16For quotation of more than 40 words, it has to written in
block and indented. Teknologi digital membolehkan kesepaduan media
untuk menyampaikan maklumat. Ini diterangkan oleh Musa Abu Hassan
(2002) seperti berikut:Antara lain teknologi digital mampu untuk
menukarkan maklumat dalam bentuk gambar, suara atau teks dalam
gabungan kod tutup dan kod buka. Teknologi digital menggunakan
urutan angka untuk melambangkan maklumat, manakala sistem analog
pula merupakan sistem yang menggunakan gelombang mikroelektronik
yang ditukarkan menjadi isyarat elektrik. (p.19)172.If making
citation from a material that quote another source, then the
reference should be made to the one who made the citation.
Example:In the writing of Ahmad, it stated that Ismadi (2001) had
found the most effective medium to disseminate information was
television. In this case you did not refer to Ismadi, but you refer
to Ahmad. Thus, your reference is Ahmad, not Ismadi.- The citation
then becomes Ahmad (cited form Ismadi, 2001) .. 3. Arranging
information that are referred- When an idea is cited form several
sources that are similar, then the authors names are written,
without repeating the same idea. Example: Nonverbal messages are
more powerful than the verbal messages at all times (Musa, 2007,
Zahid, 2008, and Roberts, 2010)- If the idea conflicts one another,
then write their names and their ideas respectively.
Writing referencesBookMitcheel, T. R., & Larson, J. R.
(1987). People in organization (3rd ed.). New York: McGraw-HillBook
chapterBjork, R. A. (1998). Retrievel inhibition as an adaptive
mechanism in human memory. In H. L. Larson & T. R. Mitcheel
(Eds.), Varieties of memory and consciousness (pp. 105-175).
Hillsdale, NJ: Erlbaum
20Journal article Klimoski, R., Palmer, S., Isomand, T. P, &
White, L. A. (1993). Role of early supervisor experience in
supervisor performance. Journal of Applied Psychology, 78,
443-44921Presented paperEzhar Tamam. (1999, May). An exploratory
study of complimenting behaviour among Malays. Paper presented the
International Conference on MICOLLAC organized by Faculty of Modern
Languages and Communication, Universiti Putra Malaysia, Serdang,
Selangor22NewspaperScheartz, J. (1993, September 30). Obesity
affect economic, social status. The Washington Post, p.7Newspaper
article without authorNew drug appears to sharply cut risk of death
from heart failure. (1995, July 15). The Washington Post,
p.1523MagazineZamri Ahmad. (1999). Mengatasi kegugupan komunikasi.
Majalah Pengembangan, 3, 65-71.Report of organizationJabatan
Penerangan Malaysia. (1995). Laporan Tahunan 1994. Kuala Lumpur:
Jabatan Penerangan
24Online journalFuller, L.K. (1998). The role of dominant
ethnicity in racism: Reportage on Chinese rule in multi-racial
Singapore. The adge: The E-Jurnal of Intercultural Relations, 1, 3.
Retrieved June 30, 1998. Available:
http://www.hart-li.com/biz/theedge/domrac.htm25CD-ROM
abstractBrower, D. L. (1995). The tip-of-the-tongue phenomena
(CD-ROM). Memory & Cognition, 20, 200-215. Abstract from:
ProQuest File: Dissertation Abstracts Item:9315947Online
source(without author and article
title)http://www.apa.org/journals/webref.html
26Writing research proposalShould include the followings:- title
of research- some scenario of the research background- the
importance of research- statement of problems, research questions,
general and specific objectives or hypotheses- key concepts and
variables- some pertinent literatures and related theory-
methodology or research design data collection method(s)-
population and sampling procedures- data processing and analysis-
research schedule and key milestone- research personnel and
research costs- expected outcomes and their importance Work
backwards for time schedule, begins with expected completion
timeIdentify key milestones that are achievableIndicate key team
meetings and workshopsThe research team members must be given
specific tasks or justify their presence List the roles of research
assistant(s)
Research budget should include:- equipment, software, upgrading,
stationeries - salary, traveling and lodging- support services for
data collection and processing, secretarial helps- communication
telephones, faxs, stamps- overheads, per diem, honorarium, tokens -
contingency (10 15 % of total)
KOM 5115STATISTICS FOR COMMUNICATION RESEARCH
Professor Hj. Musa Abu Hassan,
[email protected]@yahoo.com
Sampling Techniques
Randomization the application of the principles of random sampling
to a chunk from a population in which a number of equivalent groups
are to be established whose differences from one another can only
be attributed to chance
Simple Random Sampling (SRS)
A method of choosing cases from a population by which every case
and every combination of cases has an equal chance of being
includedEach case is selected independently of all other
membersRequires a complete population listRandom number table, pick
from hat
Systematic Sampling
A method of sampling by which the first case from a list of
population is randomly selected. Thereafter, every kth case is
selectedRequires a complete population listTotal population divided
by sample size to get the k interval
Stratified Sampling
A method of sampling by which the cases are randomly selected from
sub-lists of the population. The sampling plan can be either
proportional or disproportionate Requires a complete sub-lists of
population
Cluster Sampling
A method of sampling by which the units are randomly selected and
all the cases within each selected unit are utilizedRequires a
complete lists of geographical units Adequate sample size is very
important for inferential statistics to obtain statistical
power
Statistical Assumptions
A set of parameters, guidelines indicating the conditions under
which the statistical procedures can be most appropriately
usedEvery statistical test has its own assumption that should not
be violated
Parametric statistics require more stringent assumptions than
non-parametric statisticsThese assumptions are mostly related to
distribution, independent, randomness, and level of measurement of
the data
Inferential Statistics
To enable researchers to make statement, summary or decision:-
about the population based on the sample- on unseen data based on
the empirical data- on a large group based on data from the small
group
Assumptions of Inferential Statistics
Random sampleCharacteristics are related to true populationMultiple
random sample from same population yield similar statistics that
cluster around the population parametersCan calculate the sampling
error associated with a sample statistics
Characteristics of Normal Distribution
The distribution is continuousThe distribution is symmetrical,
bell-shaped with the mode, median and mean are equalThe
distribution contains an infinite number of cases
The distribution is asymptotic the tails approach abscissa,
ranges from negative to positive infinity (- to + )About 95% of the
distribution lies within 2 standard deviation from the
mean
Central Limit Theorem
If repeated random sample of size N are drawn from any population,
with the mean and variance then, as N becomes large, the sampling
distribution of sample means will approach normality, with mean and
variance /N
Law of Large Numbers
If repeated random sample of size N are drawn from any population,
with the mean and variance then, as N becomes large, the sampling
distribution of sample means will be normal, with mean and variance
/NA good rule of thumb is that N is 100 can be considered as large
N
Hypothesis Testing
One of the main procedures in inferential statistics is hypothesis
testingHypothesis is a tentative statement about somethingUsually
statement concerning:- differences between groups- association or
relationship between variables- changes that occur
Statistical test is used to test the hypothesisHypothesis
statement and testing help us in:- drawing conclusion- making
implication- making appropriate suggestionResult of hypothesis
testing is rejecting or failing to reject the null
hypothesis
Types of hypothesis
Null hypothesis: A statement of no difference or association among
variables, samples etc., shown as Ho:Alternative or research
hypothesis: A statement asserting that there is a difference or
association among variables, samples etc., shown as Ha: or
H1:
Related concepts
Level of significant or alpha level: The proportion of area under
the sampling distribution that contains unlikely sample outcomes
given that the null hypothesis is trueCommonly expressed as 90%,
95% or 99% or p=.10, .05, or .0195% refers to p=.05 which means we
are 95% sure of making the right decision and 5% error
Critical Region: The area under the sampling distribution that,
in advance of the test itself, is defined as including unlikely
sample outcomes given that the null hypothesis is trueCritical
value of the test statistic to reject the null hypothesis
Critical value is obtained from the test statistic table in
accordance to its level of significant and degree of freedomThe
null hypothesis is rejected when the value of test statistics
exceeds the critical value and lies in the critical
region
One-tailed test and two-tailed test: Critical region on one side
or both sides of the distribution, depending on the nature of the
alternative or research hypothesisCan use either one, researcher
decides
One-tailed test: A type of hypothesis test used when the
direction of the difference between the variables or sample can be
predictedHas one critical region that corresponds to the direction
of the alternative or research hypothesis
Two-tailed test: A type of hypothesis test used when the
direction of the difference between the variables or sample cannot
be predictedHas two critical regions on both sides of the
distribution
Type I error (alpha error): The probability of rejecting the
null hypothesis that is in fact trueType II error (beta error): The
probability of failing to reject the null hypothesis that is in
fact falseCannot make both errors
Decision Ho TrueHo False
Reject HoType I errorCorrectdecision
Fail toCorrectType IIReject Hodecisionerror
Five-Step Model for Hypothesis Testing
Step 1 Making assumption- samples selected randomly- defined
population- interval-ratio data- sampling distribution, normalStep
2 Stating null hypothesis- no difference or no association- state
the alternative hypothesis
Step 3 Select the test statistics- establish level of
significance (normally p=.05 for social sciences)- establish
critical regionStep 4 Calculate or compute the test statistics-
compare calculated value with test statistics using table
Step 5 Making decision- if test statistics falls in the critical
region, reject the null hypothesis - if test statistics does not
fall in the critical region, do not reject the null hypothesis at
the predetermined level of significance- state the
conclusion
T-test
Purpose: to test or show differences of sample meansData must be
interval or ratioThree types of T-test* one sample* two matched or
related samples* two independent sample
One sample t-test is used to test difference of one sample to
the populationt = x - x= sample means=pop. mean ns=sample std
devn=sample sizedf=n - 1
Two matched or related samples t-test is used to test difference
of two related or paired samplest = D - DD=sample mean
differentsDD=pop. mean diff =0 nsD=sample std devn=sample sizedf=n
- 1
Two independent samples t-test is used to test difference of two
samplesNeed to conduct test of variance to decide with t-test
formula to useF = large variance small variance
ANOVA
To compare means of more than two groupsAssumption for ANOVA:- each
group must be random sample from a normal population- in the
population, the variance of all groups must be equal- observation
must be independent
The dependent and independent variables must be interval or
ratio and continuousF is the statistics for ANOVATo calculate F,
use sum of squaresF = Mean square (between) Mean square
(within)
One-way ANOVA is an application of ANOVA in which the effect of
single variable on another is observedPost-hoc analysis is done to
determine which variables are really different
Chi Square
The single most frequently used statistical procedure in social
sciencesA non-parametric test of hypothesis and require nom
assumption about the exact shape of the population distributionCan
be used for single sample test and two samples test
One sample test is known as Goodness of fit to know whether
sample are randomly distributed in each categoryTwo samples test is
known as Test of independent to know whether the samples are
related or not related to one another, just like test of
association
Assumptions for Chi Square test- exhaustive category- mutually
exclusive categories- sample is random- observation is independent-
the scale of measurement is at least nominal or
categorical
General rules for Chi Square test- For 2 X 2 table, N > 20-
Not more than 20% of the expected value is less than 5 and/or
expected value or frequency is less than one and/or no expected
value or frequency = 0- If df=1, use Yates correction
Yates correction formula:X = (|O - E| - 0.5) E
Chi Square for One sample:X = (O - E) E O = observed value or
frequencyE = expected value or frequencydf = k -1 (k= no. of
categories)E= Row total X Column total Grand total
Chi Square for Two samples:X = (O - E) E O = observed value or
frequencyE = expected value or frequencydf = (r 1) (c 1) E= Row
total X Column total Grand total
Calculation of Expected value or frequency a bE c dF G HT
Expected a=ExG b=ExH c=FxG d=FxHT T T T
Bivariate Statistics
Involving two variablesMeasure of association or
relationshipMeasure of differenceCharacteristics of bivariate
association:* does an association exist?* if exist, how strong?*
what is the pattern or direction of association?
Association is the relationship between two or more variablesTwo
variables are said to be associated if the distribution of one
variable changes, the score or category of the other variable is
also changed (effected)x symbol for independent variableY symbol
for dependent variable
Positive association the variables vary in the same direction:
one increases, the other also increasesNegative association the
variables vary in opposite direction: one increases, the other
decreases
Linear relationship: a relationship between two variables in
which the observation points in the scattergram can be approximated
within a straight linePearsons r: a measure of association for
variables that have been measured at the interval-ratio
level
Pearsons Product-Moment Correlation Coefficient r * value ranges
from -1 to +1* plus and minus indicates direction of
association/relationship* 1 means perfect association* variables
must be interval-ratio and independent* the slope indicates the
strength of the association
Guildfords rule of thumbrstrength of association< 0.20Almost
negligible0.20 0.40Low correlation, small relationship0.40
0.70Moderate correlation, substantial relationship0.70 0.90High
correlation, marked relationship> 0.90Very high correlation,
very dependable relationship
Simple regression
This procedure is a big brother of correlationInvolves one
dependent variable (y) and one independent variable (x)Both
variables must be interval or ratio level of measurement and
independentThe procedure allows for making prediction about y based
on value of x
Coefficient of determination (R): the proportion of all
variation in y that is explained by x. Found by squaring the value
of Pearsons r
Regression line is shown by the formulay = a + bxy = score of
dependent variablea = the y interceptb = the slope of the
regression linex = score of independent line
The y intercept, a, can be calculated by the formula:a = y bxa =
the y intercepty = mean of yb = the slopex = the mean of
x
In regression we want to predict the value of y based on x, thus
the formula becomes
y = a + bx where y is the predicted value of y
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