study focuses on lexical errors and there are plenty of lexical errors committed by students.
This study sum up the lexical errors and classifies each type of lexical errors.
 
2  Research Design and Data Collection
2.1 Research Questions
Generally speaking, one can't learn a language without committing errors. Errors can act as
a window so that both students and researchers can benefit them. This thesis studies lexical
errors aiming to find out different types of lexical errors and explores for causes. As a result,
this study tries to answer the following questions: (1) What lexical errors non-English
major students mostly like to produce in non-English majors' writings. (2) There are many
lexical errors  committed by students. How often do non-English major learners make
lexical errors? And how to classify  these errors? (3) What are  the causes of those lexical
errors?
 
Furthermore, there will be  a discussion of the pedagogical  enlightenments to vocabulary
teaching.
 
2.2 Subject and Data Collection
The study chooses 120 students as the subjects,  60 in one class and 60 in another class
respectively. All of them are non-English majors from Nanjing University of Science and
Technology. They are all freshmen and most of them have already passed college English
test band four (CET-4). All of the students are at the same language level comparatively,
because they have passed the national entrance examination and have been taught under the
same curriculum and teaching surroundings. The students were required to write two
compositions entitled "Test for National Civil Servants" and "Supporting Traditional Arts".
Each of the compositions should contain 150-200 words. All of the students in the two
classes wrote the compositions and were observed by the researcher in the students' regular   
class. Compositions are collected for the preparation of this test, so students have great
motivation and serious attitude to the writing, which can ensure the authenticity and
reliability of the composition. The researchers of this study selected a total 120
compositions of freshmen as samples. These compositions were neither scored nor
corrected by the teacher. They were written in the second semester of students' first college
year. They were class tasks. So students did not know the title of the composition
beforehand and they were not allowed to use  any dictionary or ask for help. Therefore,
these samples can reflect natural language use and to some  extent reflect the language
competence of the students. Meanwhile, the validity of this study can be promised.  
 
2.3 Research Methods
There are two basic approaches to language  study. Qualitative research is empirical
research where the data are not in the form of numbers. Quantitative research is empirical
research where the data are in the form of data. In detail, the focus of qualitative analysis is
to use language to describe the study.  This kind of method mainly depends on the
researchers' intuition, experience as well as the situation and information of the research
object to make a judgment. While quantitative analysis refers to a method, which uses
mathematical language to describe the study.  It is a method, which is based on statistical
data to set up mathematical models and then make conclusions. Qualitative analysis is the
basis of quantitative analysis. Quantitative analysis makes qualitative analysis more
scientific and accurate, and it can promote qualitative analysis to draw an extensive and
in-depth conclusions. Therefore, in this thesis the writer combines the two methods to do
the research. Quantitative approach is characterized by its advantage in the statistical 非英语专业学生英语写作中的词汇错误分析与对策(3):http://www.youerw.com/yingyu/lunwen_4257.html