HYPOTHESIS TESTING
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Hypothesis tests are used to statistically determine the probability that a hypothesis is accepted at a given significance level. The purpose is to determine if there is enough statistical evidence to support a hypothesis. A hypothesis predicts the relationship between variables and can be tested, whereas a research question does not make a prediction. Good hypotheses are compatible with current knowledge, logically consistent, clearly stated, and testable. The null hypothesis asserts there is no difference or relationship, while the alternative or research hypothesis predicts a difference or relationship. Setting a significance level helps determine if results reject the null hypothesis.
HYPOTHESIS TESTING
- 2. HYPOTHESIS TESTING Hypothesis tests are designed to statistically determine the probability that a certain hypothesis would be considered accepted at a certain significance level or not. The purpose of hypothesis testing is to determine whether there is enough statistical evidence in favor of a hypothesis.
- 3. Research Question ? “OR” Hypothesis? • Research starts with a research question or hypothesis. • These are tentative generalization regarding a relationship between two or more variables. • There is slight difference between the research question and hypothesis. Hypothesis makes prediction about experimental outcome, research question does not.
- 4. • Research question may take the form of a simple question about the relationship between two or more variables. • It should be as specific as possible. In some cases, you may make two or more research questions to cover a complex topic. • Examples: • How much hours per day students spend on social networking sites? • Do the college students with firm career goals achieve higher GPAs than the students who do not have firm career goals? RESEARCH QUESTION
- 5. HYPOTHESIS A tentative generalization regarding the relationship between two or more variables that predict an experimental outcome. Example: The level of attention paid to radio commercials is positively related to the amount of recall of commercial.
- 6. HYPOTHESIS • A hypothesis is a statement that can be proved or disproved. • Hypothesis translates the research question into a prediction of expected outcomes. 1. How much hours per day students spend on social networking sites? 2. Do the college students with firm career goals achieve higher GPAs than the students who do not have firm career goals? 1. Students who spend more time on social networking sites are considered to be socially alienated. 2.It is hypothesized that college students who have firm career goals achieve higher GPAs than those who do not have firm career goals.”
- 7. CRITERIA FOR GOOD HYPOTHESIS Should be compatible with current knowledge in the area It should follow logical consistency A good hypothesis must be stated briefly and clearly A hypothesis should be testable
- 8. NULL HYPOTHESIS (Hypothesisof no difference) • It asserts that the statistical difference or relationship being analyzed are due to chance or random error. • The null hypothesis (H0) is the logical alternative to the research hypothesis (H1). Research Hypothesis: The level of attention paid to radio commercials is positively related to the amount of recall of commercial. Null Hypothesis: The level of attention paid to radio commercials is not positively related to the amount of recall of commercial.
- 9. BENEFITS OF HYPOTHESIS 4 MAJOR BENEFITS • PROVIDE DIRECTION OF STUDY • ELIMNINATE TRIAL AND ERROR RESEARCH • HELP RULE OUT INTERVENING AND CONFOUNDING VARIABLES • ALLOW FOR QUANTIFICATION OF VARIABLES
- 10. TESTING HYPOTHESIS • In hypothesis testing or significance testing, the researcher either rejects or accepts the null hypothesis. • That’s is, if H0 is accepted, it is assumed that H1 is rejected. • If H0 is rejected,H1 must be accepted.
- 11. Example • Consider a study of the math competency of a group of subjects who receive a special learning treatment, possibly a series of television programs on mathematics. It is hypothesized that this group after viewing the programs, will have scores on a standardized math test significantly different from those of the remainder of the population that has not seen the programs. Research Hypothesis H1= Null Hypothesis H0= Students who have received special mathematics learning TV programs will score high on Math competency test. Special mathematics learning TV programs makes no impact on score obtained in Math competency test.
- 12. Significance Level • To determine the statistical significance of a research study, the researcher must set a probability level or significance level, against which the null hypothesis is tested. If the results of the study indicate a probability lower than this level, the researcher can reject the null hypothesis. If the results of the study indicate a probability higher than this level, the researcher must support the null hypothesis.
- 13. One Tail Test: A one-tail test predicts that the results will fall in only one direction- either positive or negative. Two Tail Test: It does not predict any direction. Two tail tests are generally used when little information is available about the research area.
- 14. One -Tailed Alternative= Men earn more than women. . Two-Tailed Alternative= Wages of men and women are not equal. Research Hypothesis H1 = Wages of men and women are equal. Null Hypothesis H0 = Men earn more than women.
- 16. Critical region/region of rejection In a theoretical sampling distribution, the proportion of the area in which the null hypothesis is rejected is called the region of rejection. This area is defined by the level of significance chosen by the researcher. If the .05 level of significance is used, then 5% of the sampling distribution becomes the critical region. Conversely, the null hypothesis is retained in the region between the two rejection values.
- 17. Regions of Rejection for p ≤ .05 (Two-tail)
- 18. Finding Z (Standard score) value • It follows that corresponding z values that define the region of rejection are those that cut off 47.5% (.4750) of the area from “m” to each end of the tail. • To find this z-value, we use table:
- 19. Table 3: Areas under the Normal Curve. Proportion of Area under the Normal curve between the Mean and a z distance from the Mean.
- 20. Determination of region of rejection These values are used to determine the region of rejection. - 1.96 αm + μ = lower boundary + 1.96 αm + μ = upper boundary Where: αm = Standard deviation of the distribution μ = Population mean Assume population mean for math competency is 100 and standard deviation is 15. Mean math’s competency scores are: -1.96(15) + 100 = 70.60 +1.96(15) +100 = 129.40
- 21. Regionof Rejectionfor Math Test
- 22. CONCLUSION • If the research study produces a result between 70.60 and 129.40, a result between 70.60 and 129.40, the null hypothesis can not be rejected. TV programs had no significant effect on math competency levels.