I need to plot S-curve for the variables age and score (in precentage)' As they did in an article.

They did an arsin transformation, so first I did it by : 2 * ARSIN(SQRT(var2/100))

And then, they did logit regression And made the plot by it.

The function look like: 100*(SIN(

**2.667***EXP(-0.976+0.194*Agemon))/(2*(1+EXP(-0.976+0.194*Agemon))))**2

What I ask to know:

1. To get the regression equation, do I need to do

**regular linear regression**of age with that transformed,

**to get the coefficients a,b**for the transformation?

2. What is the number

**2.667**in the equation stand for? how I need to calculate it?

3. What is the best way to get the S plot of the Age with that function?

Thanks!

Shi