Consider the following statements, and indicate which variable is an independent variable and which variable is a dependent variable; moreover, determine whether there is a positive or a negative relationship between two variables.

a$.$ More educated employees typically have higher income than less educated employees.

Education is the $]$ vatiable.

Income is the $]$ variable.

The relationship between education and income is $($Click to select$)v.$

b$.$ Consumers with higher incomes are more likely to purchase new iPhones.

Sales of the new iPhone is the

Consumer income is the variable.

$]$ variable.

The relationship between consumer income and sales of the iPhone is

c$.$ As research shows, anti$-$smoking campaigns reduce the number of smokers in the country.

Number of anti$-$smoking campaigns is the variable.

Number of smokers is the

variable.