Significant Difference between Pre test and Post test

Where, M 1 = the mean score of the pre- test M 2 = the mean score of the post- test N = the number of the students X 1 = the number of the pre- test sores X 2 = the number of the post- test scores The computation of the mean score of the pre- test was as follows: M 1 = 33 2245 M 1 = 68, 03 The computation of the mean score of the post- test was as follows: M 1 = 33 2969 M 2 = 89, 96 The calculation of the means of the pre- test and the post- test were 68, 03 and 89, 96. If we compared the two mans it was clear that the mean of the post- test was higher than that the pre- test. The difference between the two means was 21, 93 M 2 - M 1 . It indicated that the treatment was effective. To make the analysis more reliable the writer analyzed it by using t- test formula. The effectiveness of the treatment could be calculated using the following formula: t = 1 2 − ∑ n n d x M d Where, t : t- test M d : the interval of the deviation value and the mean of deviation value n : number of sample df : the degree of freedom df : n- 1 Before applying the t- test formula, the mean of the deviation value of pre- test and post- test should be found first. The following was the process of computing the deviation value. M d = n d ∑ M d = 33 724 M d = 21, 9393 The mean of the deviation value was 21, 9393 After getting the mean of the deviation value, the computation of the t- test was as follows: t = 1 2 − ∑ n n d x M d t = 1 33 33 8817 , 8015 9393 , 21 − t = 32 33 8817 , 8015 9393 , 21 × t= 1056 8817 , 8015 9393 , 21 t= 5907 , 7 9393 , 21 t= 7551 , 2 9393 , 21 t=7, 9631 The t- value of the test was 7, 9631. For the complete data of Md, d, Xd, and Xd 2 could be seen in appendix 10.

4.3 Test of Significance

After getting the t- value, the writer consulted the critical value on the t- table to check whether the difference was significant or not. Before the experiment was conducted, the level of significance to be used in the experiment had been divided first. For this experiment, the writer used 5 0, 05 alpha level of significance as usually used in psychological and educational research. The number of subjects in this experiment was 33. The degree of freedom df was N-1= 33-1= 32. For five percent alpha level and 32 degree of freedom, there was no definite critical value in the table. It was necessary to find the definite critical value using interpolation in order to get the closest of the critical value in the t- table. t- table for 40= 2.021 60= 2.00 32=? 60 40 32 40 00 . 2 021 . 2 021 . 2 − − = − − t 20 8 021 . 021 . 2 − = − t 20t=0,168+40.42 t= 20 588 , 40 t= 2. 0294 The t- table was 2. 0294. The obtained t- value was 7, 9631 so the t- value was higher than the critical value on the table 7, 96312. 0294 From the result, it could be concluded that the difference was statistically significant. Therefore, based on the computation there was significant difference between teaching English preposition after and before using Total Physical Response. Teaching English preposition after was more effective than teaching English preposition before sing Total Physical Response. It could be seen by the result of the test where the students’ score was higher after giving treatment.