Question 6

Scenario:

The endorphins released by the brain act as natural painkillers. Some researchers wanted to monitor pain thresholds in pregnant rats the days before they gave birth to see if there was a change in pain threshold leading up to giving birth. They measured this pain threshold at 7, 5, 3 and 1 days prior to giving birth.

For this scenario, identify the independent variable(s) and the dependent variables. In addition, provide how many levels there are for the independent variable(s) being used in this study.