# Test for Equal Shapes or Scales Across Growth Curves

main topic

When your failure/repair data are from more than one growth curve, Minitab
first performs an analysis on each growth curve. Then it uses the resulting
parameter estimates
to provide a likelihood ratio test
for:

· Equal
shapes across groups -
if you do not provide a known shape

· Equal
scales across groups -
if you provide a known shape

· Equal
MTBFs
across groups - if
the shape is set at 1

The hypotheses for these tests are:

· H0: all of the shapes
(or scales or MTBFs) are equal

· H1: at least one of
the shapes (or scales or MTBFs) is different

Note These
tests are not available for interval data.