In the context of a data table that includes employees, their years of higher education, and current salary, a "variable" is typically a characteristic or attribute that can take on different values for different individuals.
Among the options provided:
- Previous salary: This could be a variable, but it is not mentioned in your context.
- Years of experience: This could be a variable, but it is also not mentioned in your context.
- Years of higher education: This is definitely a variable because it represents varying amounts of higher education across different employees.
- Average salary: This is a summary statistic, not a variable that varies, but rather an aggregate figure based on other data.
Given this information, the correct response is:
years of higher education