Types of hypothesis

It gives the basic idea about types of hypothesis

1. Types of Hypothesis Submitted by ABILASH.S II M.Sc MICROBIOLOGY

2. Agenda what is hypothesis Characters of hypothesis Types of Hypothesis Type I and II errors Importance of Hypothesis Conclusion

3. What is a Hypothesis? A hypothesis may be defined as a proposition or a set of proposition set forth as an explanation for the occurrence of some specified group of phenomena either asserted merely as a provisional conjecture to guide some investigation or accepted as highly probable in the light of established facts Etymologically hypothesis is made up of two words, “hypo” and “thesis” which means less than or less certain than a thesis

4. According to Lundberg, “A hypothesis is a tentative generalisation, the validity of which remains to be tested. In its most elementary stage, the hypothesis may be any hunch, guess, imaginative idea, which becomes the basis for action or investigation”

5. Characters of Hypothesis Hypothesis should be : clear and precise capable of being tested. state relationship between variables limited in scope and must be specific. consistent with most known facts amenable to testing within a reasonable time.

6. Types of hypothesis

7. Types of hypothesis Simple hypothesis: A simple hypothesis is a prediction of the relationship between two variables: the independent variable and the dependent variable . E.g Drinking sugary drinks daily leads to obesity . Complex Hypothesis : A complex hypothesis examines the relationship between two or more independent variables and two or more dependent variables . E.g Overweight adults who 1 ) value longevity and 2) seek happiness are more likely than other adults to 1) lose their excess weight and 2) feel a more regular sense of joy.

8. Cont.. A  logical hypothesis  is a proposed explanation possessing limited evidence. Generally, you want to turn a logical hypothesis into an empirical hypothesis, putting your theories or postulations to the test . E.g Cacti experience more successful growth rates than tulips on Mars. (Until we're able to test plant growth in Mars' ground for an extended period of time, the evidence for this claim will be limited and the hypothesis will only remain logical.)

9. Cont.. An  empirical hypothesis , or working hypothesis, comes to life when a theory is being put to the test, using observation and experiment. It's no longer just an idea or notion. It's actually going through some trial and error, and perhaps changing around those independent variables . E.g Roses watered with liquid Vitamin B grow faster than roses watered with liquid Vitamin E. (Here, trial and error is leading to a series of findings.)

10. Cont.. A  statistical hypothesis  is an examination of a portion of a population. If you wanted to conduct a study on the life expectancy of Savannians , you would want to examine every single resident of Savannah. This is not practical. Therefore, you would conduct your research using a statistical hypothesis, or a sample of the Savannian population.

11. Difference between directional and non directional Directional Hypotheses - These are usually derived from theory .They may imply that the researcher is intellectually committed to a particular outcome. They specify the expected direction of the relationship between variables i.e. the researcher predicts not only the existence of a relationship but also its nature . Non-directional Hypotheses - Used when there is little or no theory, or when findings of previous studies are contradictory. They may imply impartiality. Do not stipulate the direction of the relationship.

12. Associative and causal Hypotheses: Associative Hypotheses -Propose relationships between variables - when one variable changes, the other changes. Do not indicate cause and effect . Causal Hypotheses- Propose a cause and effect interaction between two or more variables. The independent variable is manipulated to cause effect on the dependent variable. The dependent variable is measured to examine the effect created by the independent variable

13. Null hypothesis vs Alternative hypothesis

14. Null Hypothesis : These are used when the researcher believes there is no relationship between two variables or when there is inadequate theoretical or empirical information to state a research hypothesis . The null hypothesis represents a theory that has been put forward, either because it is believed to be true or because it is to be used as a basis for argument, but has not been proved. Has serious outcome if incorrect decision is made . Designated by: Ho or Hn .

15. The Alternative Hypothesis The alternative hypothesis is a statement of what a hypothesis test is set up to establish. Designated by: H1 or Ha. It is opposite of Null Hypothesis. It is only reached if Ha is rejected. Frequently “alternative” is actual desired conclusion of the researcher

16. ERROR.. A person is on trial for a criminal offense and the judge needs to provide a verdict on his case. Now, there are four possible combinations in such a case: First Case: The person is innocent and the judge identifies the person as innocent Second Case: The person is innocent and the judge identifies the person as guilty Third Case: The person is guilty and the judge identifies the person as innocent Fourth Case: The person is guilty and the judge identifies the person as guilty

17. Types of error

18. CONCLUSION: A hypothesis is put to test for its tenability and for determining its validity. If it is proved, it becomes the solution of the problem, for which it was formulated. If it is not proved, alternate hypothesis or situations would need to be formulated and tested. A hypothesis thus stands somewhere at the midpoint of research; from here one can look back to the problem and also forward to data.

19. BOOKS REFERRED: Research Methodology By C.R. Kothari. Research Methodology in Education By Dr. K. Nagarajan , Dr. R. Srinivasan , Dr. (Mrs.) Mary Vijayakumar . Ram publishers, Chennai, 2003. Research Methods in Education By Dr. Radha Mohan. Research in Education (Ninth Edition) By John W. Best & James V. Kahn.

20. OPEN SESSION ?