power point about T- TEST - discourse analysis
- 1. t Test Arafatul Ulfa Baiq Wimandari Safitri Raudyatuzzahra Muhammad Islahuddin
- 3. T – Test is the technique of analyzing data to determine whether differences between groups are statistically significant or whether they could have occurred simply by chance. Definition of t-Test
- 4. The alternative hypothesis represented by the symbol HA or H1, Predicts whether there would be a statistically significant difference between the two means being compared. There are two types of hypothesis: a. Directional hypothesis b. Non-directional hypothesis Hypothesis for t-test
- 5. Direction al Hypothes is Predicts that a group of first-grades using whole-language approach (experimental group) would score higher on end-of-year reading test compared with a similar group of first-grades using basal readers (control group) Non- directiona l hypothesi s Predicts that there would be a difference between the two means, but the direction of the outcome is not specified. HA = MeanE > MeanC HA = Mean1 ≠ Mean2
- 6. Predicts that there will be no difference between the means. Any observed difference between the means is too small to indicate a real differences between them and that such difference is probably due to sampling error. The Null Hypothesis H0 = Mean1 - Mean2 Or: H0= Mean1 – Mean2 = 0
- 7. Tailed Test One-tailed test: if your research hypothesis is directional and you predict which ,mean will ne higher. Two-tailed test: if your research hypothesis is non- directional and you predict a difference between the means but do not specify which mean will be higher.
- 8. A t-test is used to compare two means in three different situations: 1. T – test for independent samples: the two groups whose means are being compares are independent of each other. 2. T - test for paired samples: the two means represent two sets of scores that are paired. 3. T – test for a single sample: the t test is used when the mean of a sample is compared to the mean of a population.
- 10. t TEST FOR INDEPENDENT SAMPLES The t test for independent samples is used extensively in experimental designs and in causal comparative (ex post facto) designs when means from two groups are being compared.
- 11. 1. The groups are independent of each other. 2. A person (or case) may appear in only one group. 3. The two groups come from two populations whose variances are approximately the same. Several assumptions underlying this test:
- 12. A new test preparation company, called Bright Future (BF), wants to convince high school students studying for the American College Testing (ACT) test that enrolling in their test preparation course would significantly improve the student’s ACT scores. BF select ten students at random and assigns five to an experimental group and five to a control group. The students in the experimental group participate in the test preparation course conducted by BF. At the conclusion of the course, both groups of students take the ACT test, which was given to high school students the previous year. BF conducts a t test for independent samples to compare the scores of Group 1 (Experimental X) to those of Group 2 (Control C). An example of a t test for independent samples
- 13. The study’s research (alternative) hypothesis (HA) is directional and can be described as:
- 14. The t value is computed using this formula:
- 17. This table shows a section from the table or critical values for t test:
- 18. Our decision is to reject the null hypothesis. The hypothesis stated by BF Company is confirmed: students who participated in the test-taking course scored significantly higher on the practice form of the ACT than did the control group students.
- 19. Raudyatuzzahra