Week 8 Hypothesis Design Research Methods Week 8 Hypothesis Design

Review Hypothesis testing Research Designs Before and after without control After-only with control Before and after with control Completely randomized design Randomized block design What are the advantages and disadvantages of each?

Hypotheses A research hypothesis is a predictive statement, capable of being tested by scientific methods, that relates an independent variable to some dependent variable A research hypothesis must be: clear and precise capable of being tested consistent with most known facts

Hypotheses A research hypothesis must be: clear and precise capable of being tested consistent with most known facts Generally, they are based in a theory. They support the theory, oppose it, or extend it. Why? Because theories are applicable generalizations.

Hypotheses Generally, they are based in a theory. They support the theory, oppose it, or extend it. Why? Because theories are applicable generalizations. Example: BAD: Websites help students learn GOOD: Research by Arbaugh (2014) has shown that heightened visual stimuli improve learning outcomes. His theory of visual engagement should mean that websites which cause students to visually interact with learning material will be more effective than less interactive sites.

Hypotheses GOOD: Research by Arbaugh (2014) has shown that heightened visual stimuli improve learning outcomes. His theory of visual engagement should mean that websites which cause students to visually interact with learning material will be more effective than less interactive sites. Why? The theory frames the hypothesis and the research approach. It also sets up the discussion/recommendation section after the results come in. If the results are positive, readers now know how to use the results – find websites that are visually engaging. Hypothesis: Educational websites that feature visual interaction will generate higher test scores than websites with little visual content.

A theory gives you a broader perspective. Hypotheses Hypotheses not connected to a theory cannot be generalized – they have limited use. A theory gives you a broader perspective. No theory – hypothesis about website X is supported – result? We know to use that website. With theory – Hypothesis about website X is supported – result? We know to look for and use similar websites. We have a theory for why the website was effective.

A theory gives you a broader perspective. Hypotheses A theory gives you a broader perspective. What are the theoretical underpinnings of Website learning? (Bloom’s taxonomy) Outsourcing efficiency? (Frederick Taylor) Work group processes (Organizational communication theory) ERP completion (Management/leadership theory) If your results support the theory… If your results refute the theory…

A theory gives you a broader perspective. Hypotheses A theory gives you a broader perspective. So, step 1 in creating an hypothesis – ground in a theory How? Read research in your field and see what theory they are referencing. It should be before the hypothesis. It should also be referenced in the discussion/recommendations.

Hypotheses A theory tells us why something happens, and it gives us expectations of what should happen. The theoretical underpinnings of research questions Website learning – Why are some websites more effective than others? Why are some websites more effective than classroom learning? Outsourcing efficiency – Are all outsourcing operations equally effective? What is there in their processing that makes them effective? Are they always better than local employees? Why? Work group processes – Why are some project teams more effective? Could I predict effectiveness? Could I improve effectiveness? How? ERP completion – Why are so many ERP projects failures? Can I predict failure? What steps might reduce failure? Why would they work?

Questions connect to a theory. The theory frames the hypothesis. Hypotheses Questions connect to a theory. The theory frames the hypothesis. Website learning Question - Why are some websites more effective than others? Theory - Bloom’s taxonomy of learning shows application to be a higher level of learning. Hypothesis – Website X shows the application of a principle. It will enable students to apply the principle themselves better than website X which does not show any applications.

Questions connect to a theory. The theory frames the hypothesis. Hypotheses Questions connect to a theory. The theory frames the hypothesis. Outsourcing efficiency Questions - Are all outsourcing operations equally effective? What is there in their processing that makes them effective? Are they always better than local employees? Why? Theory – Hypothesis -

Questions connect to a theory. The theory frames the hypothesis. Hypotheses Questions connect to a theory. The theory frames the hypothesis. Work group processes Questions - Why are some project teams more effective? Could I predict effectiveness? Could I improve effectiveness? How? Theory – Hypothesis -

Questions connect to a theory. The theory frames the hypothesis. Hypotheses Questions connect to a theory. The theory frames the hypothesis. ERP completion Questions - Why are so many ERP projects failures? Can I predict failure? What steps might reduce failure? Why would they work? Theory – Hypothesis -

Hypothesis - forms A research hypothesis is Null or alternative Null: local employees process HR worksheets as well as outsource company employees Alternative: outsource company employees process HR worksheets faster than local employees Alternative hypothesis is usually the one which one wishes to prove and the null hypothesis is the one which one wishes to disprove.

Hypothesis testing The level of significance: What number will you accept to show the hypothesis is proven or rejected? It is always some percentage (usually 5%). If we take the significance level at 5 per cent, then this implies that H0 will be rejected if p>.05

Hypothesis testing Decision rule or test of hypothesis: Given a hypothesis H0 and an alternative hypothesis Ha,we make a rule which is known as decision rule according to which we accept H0 (i.e., reject Ha) or reject H0 (i.e., accept Ha). We will reject the null hypothesis if condition X is found

Decision Errors Type I and Type II errors: There are two types of errors we can make. We may reject H0 when H0 is true and we may accept H0 when in fact H0 is not true. Erroneous rejection is a Type I error Erroneous acceptance is a Type II error. False positives

Decision Errors Medical example: We draw blood and find the number of white blood cells is the number we would expect. Sample = healthy null hypothesis accepted. Type II error (erroneous acceptance): The person is sick and our acceptance of equality was wrong. Next time we set our acceptance level even lower (p<.001) Now we decide the two samples are different, the null hypothesis is rejected – we decide the person is sick. If he is not, Type I error (erroneous rejection): The person is not sick but we treated them as if they were. (False positive)

Risks of type 1 and 2 errors: Decision Errors Risks of type 1 and 2 errors: The probability of making one type of error can only be reduced if we are willing to increase the probability of making the other type of error. In business situations, we balance the risks of both types of errors. A Type I error (reject in error) may involve reworking a batch of chemicals that should have been accepted, whereas a Type II error (accept in error) might mean taking a chance that an entire group of users of this chemical will be poisoned.

Two-tailed and One-tailed tests: Decision Tails Two-tailed and One-tailed tests: A two-tailed test rejects the null hypothesis if, say, the sample mean is significantly higher or lower than the hypothesized value of the mean of the population. A one-tailed test rejects the null hypothesis if the sample mean is different in one direction – we are concerned that the mean is higher only, or lower only.

Summary of the day Hypotheses have specific qualities Hypotheses should connect to some theoretical background Hypotheses have two types Hypotheses present two types of errors