Abstract:
This thesis was a survey research. The purposes of research are 1) to study the
interpersonal relationship, being a member of informal group and work efficiency of employees,
2) to compare the work efficiency of employees based on their personal factors, 3) to study
relationship between interpersonal relationship of employees and work efficiency of employees
and 4) to study relationship between being a member of informal group of employees and work
efficiency of employees. The sample consisted of 283 employees in Thai Oil Public Company
Limited and Nathalin Company Limited. The research instrument was a questionnaire. The
statistics used to analyze the data were frequency, percentage, mean, standard deviation, t-test,
One - way ANOVA and Pearson Product Moment Correlation Coefficient.
The results found that 1) the employees were in high level of interpersonal relationship and
work efficiency, moderate level of being member of informal group. 2) employees with different
ages and years of service had different work efficiency with statistically significant level of .05.
3) being a member of informal group and work efficiency of employees had a meaningful
correlation at a statistically significant level of .01. 4) interpersonal relationship and work
efficiency of employees had a meaningful correlation at a statistically significant level of .01.