An independant variable is the variable which you change in an experiment. Note you can only have 1 variable that can change in an experiment and more than one independent variable will result in an unfair experiment. An independant variable is the variable which you change in an experiment. Note you can only have 1 variable that can change in an experiment and more than one independent variable will result in an unfair experiment. A dependent variable is the measure of the independent variable. Therefore it depends on the independent variable. Weight depends on the amount of food (in calories) we eat. The more we eat, the more weight we gain. Weight is the dependent variable. The amount we eat is the independent variable.
Used to establish cause-effect when experimental design not possible for legal, physical, ethical, or financial reasons Example: effects of smoking on health (even if ethical, might take 15 yrs to get answer and we might not want to wait)
How does preschool attendance affect social maturity at the end of the first grade? The grouping variable is preschool attendance (i.e.; the variable can take one of the two values students attending preschool and student not attending). the dependent variable or effect is social maturity at the end of the first grade . The research identifies the group of first grade who attend the preschool and a group who did not, gathers data about their social maturity, and then compares the two groups. How does having a working mother affect a child’s school absenteeism? The grouping variable is the employment status of mother (again with 2 possible values the mother work or mother does not work); the dependent variable is absenteeism, measured as number of day absent. The researcher identifies the group of students who have working mother and group whose mother don’t work, gather information about their absenteeism and compares the groups.
Chapter 7 Decision Support Systems and Marketing Research On Line: Hershey Go to Hershey’s and read its Idea Submission Policy under Consumer Info. Do you think the policy is a good idea? Notes: In home personal interviews: Provide high-quality information, but are expensive because of travel time and mileage costs for the interviewer. Not a popular survey tool. Mall Intercept interviews: Conducted in shopping malls or in a marketing research office in the mall. Surveys must be brief. It is hard to get a representative sample of the population. Telephone interviews: Cost less and provide one of the best samples of any traditional survey procedure. Many facilities for telephone interviews utilize computer-assisted interviewing, where information is directly input into a computer application. Mail Surveys: Benefits are low cost, elimination of interviews, centralized control, and anonymity for respondents. However, mail questionnaires usually produce low response rates. Executive interviews: Survey involves businesspeople at their offices regarding industrial products or services. This type of interviewing is expensive, due to the process of finding, qualifying, and interviewing respondents. Focus groups: A type of personal interviewing, characterized by seven to ten people gathered in a meeting place. The interaction provides group dynamics, with an interplay of responses yielding richer information than individual interviews.
Chapter 7 Decision Support Systems and Marketing Research Marketing researchers must be aware of the trade-offs when collecting primary data through the three main types of questionnaires.
Chapter 7 Decision Support Systems and Marketing Research Notes: Questionnaires contain three basic types of questions: Open-ended questions Closed-ended questions Scaled-response questions. Examples of these types of questions are shown on the next slide and in Exhibit 7.5.
Chapter 7 Decision Support Systems and Marketing Research
Causal comparative n survey
EDU702 Research MethodologyQuantitative Research Prepared by Azurawati Binti Wok Zaki 2011313879 ED7701A2
Chapter 16:Causal-Comparative Research (Ex post facto ResearchNon-experimental research)
TH E AI M to determine the cause of existing differences among groups.
Causal-Comparative Research is Differentiated from Experimental Research• In an experiment, the independent variable is manipulated by the researcher.• In causal comparative research the independent has already occurred. – Examples of independent variables include socioeconomic status, pre-school history, number of siblings, and so on.
Causal- comparative and Correlational Research• Similarities: researchers explore relationship among variables seek identify variables that are worthy of later exploration through experimental research. provide guidance for subsequent experimental studies. attempt to explore causation
Differences: Causal-Comparative vs Correlational- Compare 2 or more - Require a score on eachgroups of subjects variable for each subject.-Involve at least one - Investigate 2 (or more)categorical variables quantitative variables(group membership)- Often compare averages - Analyse data usingor use crossbreak tables. scatterplots
Causal-comparative and Experimental Research• Similarities:• - Require at least one categorical variable (group membership).• - Compare group performances (average score) to determine relationship.• - Both typically compare separate group of subjects.
Differences: Causal-Comparative vs Experimental-No manipulation takes -Independent variable isplace manipulated- Provide much weaker evidence forcausation than do experimental studies.- The group are already formed (the - The researcher can assign subjects toresearcher must locate them) treatment groups - The researcher has much greater flexibility in formulating the structure of the design.
Value of Causal Comparative Research• Uncovers relationships to be investigated experimentally.• Used to establish cause-effect when experimental design not possible.• Less expensive and time consuming than experimental research.• Note: if you conduct a quantitative research study it most likely will be a causal-comparative study.
More Examples of Causal Comparative Research• A researcher measured the mathematical reasoning ability of young children who had enrolled in Montessori schools and compared the scores with a group of similar children who had not been to Montessori schools.• A researcher measured the frequency of students’ misbehavior at schools which use corporal punishment and compared that to schools which did not use corporal punishment.
More Examples of Causal Comparative Research• A researcher compared the high school dropout rate between students who had been retained (held back) in elementary school vs. similar students who had not been retained• A researcher formed 3 groups of preschoolers – those who never watched Sesame Street, those who watched it sometimes, and those who watched it frequently – and then compared the 3 groups on a reading readiness test
• More Examples:• How does preschool attendance affect social maturity at the end of the first grade?• How does having a working mother affect a child’s school absenteeism?
atsT hre • Subject Characteristics • - Matching the subjects • - Finding or Creating Homogeneous Subgroups • - Statistical Matching
Data Analysis in Causal- Comparative Studies• To construct frequency polygon• Means and standard deviations are usually calculated in the variables involved are quantitative.• The most used test is a t-test for differences between means.• Analysis of covariance is useful.• The results should always be interpreted with caution.
Chapter 17: Survey Research The most popular technique for gathering primary data in which aresearcher interacts with people to obtain facts, opinions, and attitudes.
Types of Surveys i) Cross-sectional study• A study in which various segments of a population are sampled. E.g. managers and non-managers.• Data are collected at a single moment in time.• When an entire population is surveyed: Census
example• A professor of Mathematics might collect data from a sample of all the high school mathematics teachers in a particular state about their interests in earning a master’s degree in Mathematics from his university.
ii) Longitudinal study• Longitudinal survey• - information is collected at different points in time in order to study changes over time.
3 Longitudinal designsTrend study Cohort Panel Study Studydifferent a particular the researchersamples from a population surveys thepopulation whose members same sample ofwhose member do not change individuals atmay change are over the course different timessurveyed at of the survey. during thedifferent course of thepoints in time. survey.
Examples:• Trend study:- A researcher might be interested in the attitudes of high school principals towards the use of flexible scheduling. He would select a sample each year from a current listing of high school principals throughout the year. The same individual would not be the sampled each year, he would compare responses from year to year to see whether any trends were apparent.
Cohort study• A researcher would like to study growth in teaching effectiveness of all the 1st year teachers who had graduated in the past 5 years from a university. The names of all would be listed, and different sample would be selected from this listing at different times.
Panel study• A researcher select a sample of last year’s graduates from a university who are 1st year teachers and survey on the same individual several times during the teaching years.
Steps taken Defining the problem - It should be interesting and Identifying theimportant to motivate target populationindividuals to respond.
Forms of Survey Research Internet surveys Mail SurveysPersonal Interviews Telephone surveys
Comparison of three kinds of surveys SURVEY TECHNIQUES COMPARISON OF
Advantages and Disadvantages Direct Tele- Mail Inter- Administration phone viewComparative Cost Lowest Inter- Inter- High mediate mediateFacilities needed? Yes No No YesRequire training of questioner? Yes Yes No YesData collection time Shortest Short Longer LongestResponse rate Very high Good Poorest Very HighGroup administration possible Yes No No YesAllow for random sampling? Possibly Yes Yes YesRequire literate sample? Yes No No NoPermit follow-up-questions? No Yes Yes YesEncourage response to Somewhat Somewhat Somewhat Weaksensitive topics?
Questionnaire Design An interview question that encouragesOpen-Ended an answer phrased in respondent’s Question own words. An interview question that asksClosed-Ended the respondent to make a selection Question from a limited list of responses.
AdvantagesClosed-ended Open-ended-Enhance consistency of response - Allow more freedom of responseacross respondents-Easier and faster to tabulate - Easier to construct- More popular with respondents - Permit follow-up by interviewer Disadvantages- May limit breadth of response - Tend to produce responses that are consistent in length and content across respondents- Take more time to construct - Both questions and responses subjects to misinterpretation- Require more questions to cover the - Harder to tabulate and synthesizeresearch topic
Typical problems in wording questions TYPICAL PROBLEMS IN WORDING QUESTIONS
Respondent Error• A classification of sample bias resulting from some respondent action Non-response -Total Nonresponse
Non-response-total nonresponse• Not enough people respond or refuse to respond• NONRESPONDENTS - People who refuse to cooperate• NOT-AT-HOMES• SELF-SELECTION BIAS especially in case of self- administered questionnaire. People respond to only those they like.
Item Nonresponse- The respondent may not know the answer to a particular question, the respondent may find the questions embarrassing or irrelevant.