How do I perform a stretched exponential curve fit?

Stretched exponential curve fits:

• Equations of the form: y = 1 – exp[ -(t / tau)^b]
• This can cause a problem because KaleidaGraph could be trying to take a root of a negative value.
• To solve the problem, rewrite the equation as: y = 1 – 1 / [exp((t / tau)^b)]