In: Math
An experimenter is investigating the effects of noise on the performance of a tracking task. The task is to use a mouse to keep a cursor on a computer screen on a randomly moving target dot. The dependent variable is the amount of time a person can keep the cursor on the dot. It was hypothesized that subjects performing the task when no environmental noise is present will keep the cursor on the target for a greater amount of time than subjects who perform the task while listening to loud noise.
Each action by the experimenter that is described next confounds this experiment by letting an extraneous variable vary systematically with the independent variable of noise condition. For each action, identify the extraneous variable confounding the experiment and explain why the experiment is confounded.
3a. [1 point] The experimenter assigned ten 20-year-old males to the no-noise condition and ten 60-year-old females to the noise condition. |
3b. [1 point] The experimenter urged the subjects in the no-noise condition to try very hard, but forgot to encourage the subjects in the noise condition. |
3c. [1 point] Subjects in the no-noise condition performed the experiment at 9:00 A.M. and subjects in the noise condition performed the experiment at 4:00 P.M. |
3d. [1 point] The experimenter let participants choose which group (no-noise or noise condition) they wanted to be assigned to. |