ChapterⅠ Introduction 1
1.1 Statement of the Problem 1
1.2 Purpose of the Study and Research Questions 2
1.3 Theoretical Background 3
1.3.1 English Language Learners and the Inequality in Education 3
1.3.2 Language Proficiency in Academic Settings 4
1.3.3 Accommodation for ELLs 5
1.4 Chapter Summary 6
1.5 Assumptions of the Study 7
1.6 Limitations of the Study 7
ChapterⅡ Literature Review 8
2.1 Research on the Relationship between Language and Math Achievement 8
2.1.1 AConfirmed Relationship 8
2.1.2 AChanging Relationship 8
2.1.3 Other Variables of Interest 10
2.2 Limitations of Past Researches 12
2.2.1 Limitations in Research Designs 12
2.2.2 Limitations in Statistical Modeling 13
2.3 Quantile Regression:Basics and Applications 14
2.3.1 QRM in Equations 15
2.3.2 QRM Parameter Estimation 16
2.3.3 QRM Standard Error Calculation and Confidence Interval 17
2.3.4 Hypothesis Testing 18
2.3.5 QRM Goodness-of-fit Index 19
2.3.6 QRM Coefficients as Measures of Location,Scale and Skewness Shifts 20
2.4 QRM Applications in the Educational Field 23
2.5 Chapter Summary 25
ChapterⅢ Data and Modeling 26
3.1 Research Questions as a Review 26
3.2 Data 26
3.3 Models 31
ChapterⅣ Results 33
4.1 Grade Level Results 34
4.1.1 Overall Model Fit 34
4.1.2 lndividual Variable Effects 36
4.2 Longitudinal Results 53
4.2.1 Modeling Building 53
4.2.2 Results 59
4.3 Summary 74
ChapterⅤ Discussion 76
5.1 Implications 76
5.2 Limitations and Future Researches 78
References 80
Appendix A:Variable Summary 89
Appendix B:Descriptive and Diagnostic Statistics 90
Appendix C:Grade Level Model Comparison Statistics 94
Appendix D:Grade Level Full Model 97
Appendix E:Full Quantile Process Plot by Grade 104
Appendix F:Khmaladez Test at Grade Level 108