Abstract:
Purposes 1.To find out the relationship between vocabulary understanding and reading comprehension of Prathom Suksa Two students. 2. To compare the achievement of each group in vocabulary understanding and reading comprehension of Prathom Suksa Two students of Chulalongkorn University Demonstration School (Elementary) which groups students according to their abilities. Procedures The two achievement tests constructed by the investigator consisted of 95 items of a vocabulary understanding test and 50 items of a reading comprehension test. They were quite easy but highly discriminating. The reliability of the vocabulary understanding test was 0.735 and that of the reading comprehension test was 0.736. The investigator sent the two achievement tests to test the subjects who were 243 Prathom Suksa Two students of Chulalongkorn University Demonstration School (Elementary). The Arithmetic Mean of the test score was used to determine the average ability in vocabulary understanding. The Percentile Rank was used to indicate the ability in reading comprehension. The Pearsons Product Moment Correlation Coefficient was used to find out the correlation coefficient between vocabulary understanding and reading comprehension abilities. The investigator compared the achievement in vocabulary understanding and reading comprehension abilities of each group by using One-Way Analysis of Variance. The Scheffes Multiple Comparison on Treatment Means was used to determine which groups were differed both in vocabulary understanding and reading comprehension abilities. Results and Conclusion: The major findings were as follows: 1. The abilities in vocabulary understanding and reading comprehension were high. 2. The correlation coefficient between vocabulary understanding and reading comprehension was 0.627 at statically significant .05. 3. The results of comparing the achievement in vocabulary understanding and reading comprehension ability between higher group, medium group, and lower group, at statically significant .05 were; 3.1 The groups that were significantly different in vocabulary understanding and reading comprehension abilities were; Prathom 2/1 (higher group) was higher than Prathom 2/2 (lower group) Prathom 2/3 (medium group) was higher than Prathom 2/2 (lower group) 3.2 The group that were not significantly different in vocabulary understanding and reading comprehension abilities were; Prathom 2/1 (higher group) and Prathom 2/3 (medium group) Prathom 2/1 (higher group) and Prathom 2/5 (medium group) Prathom 2/1 (higher group) and Prathom 2/6 (medium group) Prathom 2/1 (higher group) and Prathom 2/7 (medium group) Prathom 2/4 (medium group) and Prathom 2/2 (lower group) Prathom 2/3 (medium group) and Prathom 2/5 (medium group) Prathom 2/3 (medium group) and Prathom 2/6 (medium group) Prathom 2/4 (medium group) and Prathom 2/7 (medium group) Prathom 2/5 (medium group) and Prathom 2/6 (medium group) Prathom 2/5 (medium group) and Prathom 2/7 (medium group) Prathom 2/6 (medium group) and Prathom 2/7 (medium group) 3.3 Some groups were significantly different in vocabulary understanding but were not significantly different in reading comprehension. The groups that have higher achievement in vocabulary understanding were; Prathom 2/1 (higher group) was higher than Prathom 2/4 (medium group) Prathom 2/5 (medium group) was higher than Prathom 2/2 (lower group) Prathom 2/6 (medium group) was higher than Prathom 2/2 (lower group) Prathom 2/3 (medium group) was higher than Prathom 2/4 (medium group) Prathom 2/3 (medium group) was higher than Prathom 2/7 (medium group) Prathom 2/5 (medium group) was higher than Prathom 2/4 (medium group) Recommendation: Based on the above findings, the recommendation for further research is the study of the relationship between vocabulary understanding and reading comprehension abilities of other grades in elementary schools or in secondary schools.