A student wants to determine how his classmates feel about school. He does a survey away from school so all participants will be willing to answer freely. In several cases, younger siblings of his classmates are present, so he lets them take the survey too. He surveys a total of 50 students. Has he done a well-designed, controlled experiment? Select the correct answer. No. His data includes outliers. Yes. His sample size is relatively large. Yes. He did the survey away from school. No. His independent variable is not controlled

This type of variable is a determining factor, condition or cause for a given result, effect or consequence. It is the factor manipulated by the researcher in order to determine the relationship of the factor with the observed phenomenon, to see what influence it has on a possible result.

As we can see in the question above, it is not possible to control the independent variable in the student's experiment, for this reason his experiment cannot be considered well designed. In this experiment, it is even difficult to recognize which is the independent variable, since we have nothing to influence students' feelings about the school.