Abstract
M.Sc.
The brightness of many stars vary over time. A plot of the brightness against
time is known as a light curve. The fall and rise times of the light curve can be
modelled by two cross-correlated white noise processes.
We propose four statistics to test the hypothesis of a constant mean fall and rise
time of the light curve against the alternative that at least one of the fall or rise
times exhibits a change in mean. The asymptotic null distributions of the test
statistics are derived. The power of these four test statistics will be compared via
Monte Carlo simulations for a few alternatives. The use of these test statistics is
illustrated by application to data from the variable stars R Camelopardalis and
R Cassiopeiae.