Abstract:
The purpose of this study was to examine a level of opinions towards product quality
and service quality of Phet Ruang Supply, Co, Ltd. Also, this study aimed at investigating a level
of customer loyalty to Phet Ruang Supply, Co, Ltd. The last purpose of this study was to
determine the relationship among product quality, service quality, and customer loyalty to Phet
Ruang Supply, Co, Ltd. The data were collected by using a questionnaire, which were completed
by 212 customers using services at Phet Ruang Supply, Co, Ltd. The descriptive statistical test,
including frequency, percentage, means, and standard deviation, was used to analyze the collected
data. Also, the inferential statistical test, the test of Pearson Product Moment Coefficient, was
administered to test the research hypotheses.
The results of the study revealed that the customers knew about Phet Ruang Supply,
Co, Ltd. from words of mouth. Most of the subjects were customers using transporting service or
buying foods on a daily basis from Phet Ruang Supply, Co, Ltd. The subjects rated their opinions
towards the product quality provided by Phet Ruang Supply, Co, Ltd. at a high level. When
considering each aspect, the one in relation to the consistent performance was rated the highest,
followed by the aspects of reliability and safety, respectively. Also, the subjects rated their
opinions toward the level of service quality at a high level. In particular, all aspects of service
quality were rated at a high level. In addition, it was shown that there were high relationship
among product quality, service quality, and customer loyalty to Phet Ruang Supply, Co, Ltd.
(r = 0.728). Finally, when considering each aspect, a moderate relationship was found between
the product quality and customer loyalty (r = 0.564). Finally, there was a high relationship
between service quality and customer loyalty to Phet Ruang Supply, Co, Ltd. (r = 0.736) at a
significant level of .01.