The independent variable is number of laptops and dependent variable is grades.
Variables are classified into two categories
(i) Dependent Variables is defined as the variable whose value depends on other variable.
(ii) Independent Variables id defined as the variable whose value are not affected by any change .
For Example : y=x+3, here x is an independent variable and y is a dependent variable as any change in x will lead to change in y.
In the given question
"number of laptops available to students at john's school lead to higher grades."
In the above statement the number of grades is dependent on the number of laptops available to students in school.
Therefore , The independent variable is number of laptops and dependent variable is grades.
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