Hypothesis Testing
Hypothesis testing refers to the process of choosing between two hypothesis statements about a probability distribution based on observed data from the distribution.
Hypothesis testing is a step-by-step methodology that allows you to make inferences about a population parameter by analyzing differences between the results observed (the sample statistic) and the results that can be expected if some underlying hypothesis is actually true.
Hypothesis Testing
Hypotheses bring clarity, specificity and focus to a research problem, but are not essential for a study.
You can conduct a valid investigation without constructing a single formal hypothesis.
On the other hand, within the context of a research study, you can construct as many hypotheses as you consider to be appropriate.
Hypothesis has certain characteristics:
It is a tentative proposition.
Its validity is unknown.
In most cases, it specifies a relationship between two or more variables
The null hypothesis is a statement containing a null, or zero, difference. It is the null hypothesis that undergoes the testing procedure, whether it is the original claim or not. The notation for the null hypothesis H0 represents what is assumed to be true.
The alternative statement must be true if the null hypothesis is false. An alternative hypothesis is represented as H1. It Is the opposite of the null and is what you wish to support.
Hypothesis testing is a formal procedure for investigating our ideas about the world using statistics. It is most often used by scientists to test specific predictions, called hypotheses, that arise from theories.
There are 5 main steps in hypothesis testing:
- State your research hypothesis as a null (Ho) and alternate (H1) hypothesis.
- Collect data in a way designed to test the hypothesis.
- Perform an appropriate statistical test.
- Decide whether the null hypothesis is supported or refuted.
- Present the findings in your results and discussion section.
- Though the specific details might vary, the procedure you will use when testing a hypothesis will always follow some version of these steps.
- Hypothesis Testing Procedure
Step 1: State your null and alternate hypothesis
After developing your initial research hypothesis (the prediction that you want to investigate), it is important to restate it as a null (Ho) and alternate (H1) hypothesis so that you can test it mathematically.
The alternate hypothesis is usually your initial hypothesis that predicts a relationship between variables. The null hypothesis is a prediction of no relationship between the variables you are interested in.
E.g. You want to test whether there is a relationship between gender and height. Based on your knowledge of human physiology, you formulate a hypothesis that men are, on average, taller than women. To test this hypothesis, you restate it as:
Ho: Men are, on
average, not taller than women.
H1: Men are, on average, taller than women.
Step 2: Collect data
For a statistical test to be valid, it is important to perform sampling and collect data in a way that is designed to test your hypothesis. If your data are not representative, then you cannot make statistical inferences about the population you are interested in.
E.g. To test differences in average height between men and women, your sample should have an equal proportion of men and women, and cover a variety of socio-economic classes and any other variables that might influence average height.
You should also consider your scope (Worldwide? For one country?) A potential data source in this case might be census data, since it includes data from a variety of regions and social classes and is available for many countries around the world.
Step 3: Perform a statistical test
Step 4: Decide whether the null hypothesis is supported or refuted
Step 5: Present your findings
Report Presentation
Report formats are likely to vary with the researcher conducting the project and the nature of the project itself.
Hence, the following is intended as a guideline from which the researcher can develop a format for the research project at hand.
Most research reports include the following elements:
Report Presentation
(a)Background to the problem
(b)Statement of the marketing problem
(c)Statement of the research objectives – information needs
(a) Research design
(b) Plan of data analysis and means of interpreting results
Report Presentation
(a) Letter of authorisation
(b) Questionnaire development and pre-testing
(c) Questionnaires, forms, interview guides
(d) Sampling techniques, including error and confidence levels
(e) Fieldwork
(f) Lists including contact individuals and organisations
The results may be presented in several chapters of the report.
Report Presentation
Submission letter - A formal report generally contains a letter of submission that delivers the report and summarises the researcher’s overall experience with the project, without mentioning the findings.
Title page - The title page should include the title of the report, information (name, address and telephone number) about the researcher or organisation conducting the research, the name of the client for whom the report was prepared, and the date of release.
Table of contents - The table of contents should list the topics covered and the appropriate page numbers. In most reports, only the major headings and subheadings are included. The table of contents is followed by a list of tables, a list of graphs, a list of appendices and a list of exhibits.
Executive summary - An executive summary is a thorough overview of a research report or other type of document that synthesizes key points for its readers, saving them time and preparing them to understand the study's overall content.
Problem definition - The problem definition section of the report gives the background to the problem.
Approach to the problem and research design - The approach to the problem section should discuss the broad approach that was adopted in addressing the problem. The research design should specify the details of how the research was conducted, preferably with a graphical presentation of the stages undertaken, showing the relationships between stages. This should detail the methods undertaken in the data collection from secondary and primary sources. These topics should be presented in a non-technical, easy-to-understand manner.
Results. The results section is normally the longest part of the report and may entail several chapters. It may be presented in any of the following ways.
For example, in a health care marketing survey of hospitals, the results were presented in four chapters. One chapter presented the overall results, another examined the differences between geographical regions, a third presented the differences between for-profit and non-profit hospitals, and a fourth presented the differences according to bed capacity.
For example, a study may contain significant elements of secondary data collection and analyses, a series of focus group interviews and a survey. The results in such circumstances may be best presented by drawing conclusions from one method before moving on to another method. The conclusions derived from focus groups, for example, may need to be established to show the link to a sample design and questions used in a survey.
There may be a series of research objectives whose fulfillment may incorporate a variety of data collection methods and levels of analysis. In these circumstances the results combine methods and levels of analyses to show connections and to develop and illustrate emerging issues.
Conclusions and recommendations - Presenting a mere summary of the quantitative or qualitative findings is not enough. The researcher should interpret the results in light of the problem being addressed to arrive at major conclusions.
Report writing
Readers - A report should be written for a specific reader or readers: The report should take into account the readers’ technical sophistication and interest in the project as well as the circumstances under which they will read the report and how they will use it. Technical jargon should be avoided. If some technical terms cannot be avoided, briefly define them in an appendix.
Often the researcher must cater to the needs of several audiences with different levels of technical sophistication and interest in the project. Such conflicting needs may be met by including different sections in the report for different readers or separate reports entirely.
Report writing
Easy to follow - The report should be easy to follow. It should be structured logically and written clearly. Headings should be used for different topics and subheadings for subtopics. Clarity can be enhanced by using well-constructed sentences that are short and to the point. The words used should express precisely what the researcher wants to communicate. Difficult words, slang should be avoided. An excellent check on the clarity of a report is to have two or three people who are unfamiliar with the project read it and offer critical comments. Several revisions of the report may be needed before the final document emerges.
Report writing
Presentable and professional appearance - The look of a report is important. The report should be professionally reproduced with quality paper, typing and binding. The typography should be varied. Variation in type size and skilful use of white space can greatly contribute to the appearance and readability of the report. However, a balance should be sought with styles of variation. Too much variation can lead to confusion; variation is only useful if it aids understanding.
Report writing
Reinforce text with tables and graphs - It is important to reinforce key information in the text with tables, graphs, pictures, maps and other visual devices. Visual aids can greatly facilitate communication and add to the clarity and impact of the report.
Reinforce tables and graphs with text - Conversely it is important to illustrate tables and graphs with verbatim quotes from questionnaires and interviews. Quotes can bring to life the meaning in tables and graphs and, used carefully, can make the reading of the report far more interesting than a solid body of statistics.
Report writing
Terse - A report should be terse and concise. Anything unnecessary should be omitted. If too much information is included, important points may be lost. Avoid lengthy discussions of common procedures. Yet brevity should not be achieved at the expense of completeness.
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