QUESTION 5 5.1 Jack conducted an investigation to determine the effect of exercise on skin temperature. He asked 40 students at his school to participate in the investigation. A purposive sampling consisted of 40 boys of the same age. The investigation was done as follows: NSC AR The students were divided into two groups of 20 each (Groups 1 and 2). The skin temperature was measured for all the participants. Group 1 was asked to run around the sports field for 10 minutes. Group 2 was asked to remain seated on the benches next to the field for 10 minutes. After 10 minutes the skin temperature of all the participants was measured an the average was calculated for each group (1 and 2). 5.1.1 Identify the independent variable in this investigation​