Estimating parameters for growth curves

When you use a parametric growth curve to evaluate failure data, Minitab provides three methods for estimating the parameters.

• Maximum likelihood estimation (MLE)
• Conditional maximum likelihood estimation (CMLE)
• Least squares estimation (LSE)

This table summarizes the features available with each estimation method.

Feature	MLE	CMLE	LSE
Exact standard error and confidence interval for the shape	No	Yes	No
Asymptotic standard error and confidence interval for the shape	Yes	No	No
Asymptotic standard error and confidence interval for the scale	Yes	No	No
Non-iterative solutions, even when data are from multiple systems	No	Yes	Yes
Comparison of estimates between growth curves	Yes	Yes	No
Available for interval data	Yes	No	Yes
Available when the shape is specified	Yes	No	Yes