Lyndon is investigating whether putting plastic on her windows will help seal out cold winter drafts. She covers a window on the south side of her house with plastic and measures the inside temperature near the window. She also measures the inside temperature near a window without plastic on the north side of her house. The windows are the same size and design. Why is this not an ideal controlled investigation?
Answers
In the given case, Lyndon's experiment exhibits two independent variables, that is, one covered with plastic or not covered with plastic and the other is a measurement of the temperature on the south side or measurement of the temperature on the north side.
Thus, when Lyndon witnesses the outcomes of her experiment, she would not be able to tell that which variable generated the results she is observing. Therefore, it is not an ideal investigation.
It is not an idea controlled investigation because Lyndon's experiment, unfortunately, has two independent variables.
1) Some areas are covered in plastic whereas some are not.
2) She measures the temperature of the north and south side.
So therefore as a result when she sees the inference she is not sure the inference is the result of which variable.