"In American History, 20 students failed. Only 11 students failed World History. American History must be a more difficult course than World History." This statement is criticized because the measurement "number of students who fail" is being used as an indicator of "course difficulty." Thus, "number of students who fail" is claimed to be A) invalid. B) confounded. C) unreliable. D) biased. E) categorical.
Explanation: In statistics, a confounding variable, also called a confounding or confounding factor, is a variable that influences both the dependent and the independent variables, causing a spurious association.
