Normal Curve with average and SD sliders

When ave = 0 and SD = 1, the curve is the standard normal curve. Move the sliders to see what happens to the curve as the average and standard deviation increase and decrease.
Answer the questions below in your own words. 1. What happens to the curve as the average changes? 2. What happens to the curve as the SD changes? 3. Why is the SD only allowed to be a positive number?