1. Introduction to Statistics for Built
Environment
Course Code: AED 1222
Compiled by
DEPARTMENT OF ARCHITECTURE AND ENVIRONMENTAL DESIGN (AED)
CENTRE FOR FOUNDATION STUDIES (CFS)
INTERNATIONAL ISLAMIC UNIVERSITY MALAYSIA

2. The next step after the sample is identified and
selected using one or more of the techniques
discussed earlier, is to determine the best way
to reach respondents in order to obtain the
required data.
As a basic rule, the researcher must choose the
method that provides the most information at
minimum cost.
Data collection methods

3. Business Statistics: A Decision-
Making Approach, 7e © 2008
Prentice-Hall, Inc.
Data Collection Methods
Questionnaires surveyExperiments
Telephone
interview
Direct observation and personal
face-to-face interview
Mail / Postal
questionnaires
Data collection methods cont…

4. 1.THE EXPERIMENT: a test or treatment is
deliberately imposed on the individuals/subject in
order to observe a possible change in the response
or variable being measured.
Advantages: results in a new and more accurate
finding, subject will respond (or not) and the
experimenter may be able to measure the result.
Disadvantages: may be time consuming and costly.
Data collection methods cont…

5. 2. THE FACE-TO-FACE INTERVIEW: a.k.a. the
personal interview where the interviewer asks the
questions and records responses.
Advantages: results in a higher response rate,
peoples will respond spontaneously when
interviewed personally, the interviewer may be
able to detect false information.
Disadvantages: may be costly, the interviewer must
be carefully selected, facial expressions and
statements by interviewers may influence and
affect responses.
Data collection methods cont…

6. 3. THE TELEPHONE INTERVIEW: a usually short
interview where the interviewer asks questions
from a prepared questionnaire.
Advantages: less expensive than face-to-face
interviews, allows the researcher to monitor the
recorded telephone interviews.
Disadvantages: lower response rates, limited to a
few questions as it may not be convenient for
respondents to answer too many questions.
Data collection methods cont…

7. 4. THE QUESTIONNAIRE SURVEY: here the researcher
will personally explain to respondents his/her intentions
before giving them a questionnaire.
Advantages: speed in obtaining required data, higher
response rate, the interviewer is available to attend to
any query by respondents.
Disadvantages: expensive as it may involve considerable
transportation expenditure, research coverage may not
be as large as that achieved with the postal
questionnaire.
Data collection methods cont…

8. 5. MAIL OR POSTAL QUESTIONNAIRE: here a
questionnaire is sent to each respondent, with a request
to answer and return the questionnaire within a certain
period of time.
Advantages: cheaper than the personal interview, it
allows for greater research coverage, there is no
interviewer influence, sufficient time given to
respondents to think of appropriate answers.
Disadvantages: low response rate, there is nobody who
could readily explain unclear questions to respondents,
no way of detecting false data, may be filled by a team
not an individual thus rendering it useless, there may be
a considerable delay before enough replies are received.
Data collection methods cont…