Graph > Graph builder > Addition of spline 'smoother'

[#1]

Good morning, 

I lack the statistical information on the 'confidence of fit' tick box provided together with the spline function smoother.

1) how is this confidence of fit calculated?

2) which methodology is used to establish the 'confidence of fit' and which alpha or confidence interval is applied?

Below, the script of the graph i am currently using, just for reference. 

Many thanks in advance, 

Diogo

Graph Builder(
	Size(1526, 859),
	Variables(X(:"Hold-time [h]"n), Y(:"Viability (%)"n)),
	Elements(Points(X, Y, Legend(3)), Smoother(X, Y, Legend(4), Confidence of Fit(1))),
	SendToReport(Dispatch({"Smoother"}, "", OutlineBox, {Close(0)}))
)

Edit (jthi): added JSL formatting

[#2]

The confidence of fit region for the spline and other smoothers is calculated as a bootstrap interval based on the Graph Builder alpha value, which can be changed from the default 0.05 via the main Graph Builder red triangle menu. The number of bootstrap samples is 300.

See also: How does JMP construct confidence interval for spline fit in Graph Builder? - JMP User Community