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Virtualization treatment of control variables.
| Independent variable | Assignment method | |||
|---|---|---|---|---|
| Gender | ||||
| Gender 1 | Male = 1 | Female = 0 | ||
| Grade | ||||
| Grade 1 | Freshman = 1 | Sophomore = 0 | Junior = 0 | Senior = 0 |
| Grade 2 | Freshman = 0 | Sophomore = 1 | Junior = 0 | Senior = 0 |
| Grade 3 | Freshman = 0 | Sophomore = 0 | Junior = 1 | Senior = 0 |
