1. Explain how a time-series design minimizes most threats to internal validity from time-related variables. 2. Longitudinal research can be very time-consuming, however, this is not a problem with...

1. Explain how a time-series design minimizes most threats to internal validity from time-related variables.

2. Longitudinal research can be very time-consuming, however, this is not a problem with cross-sectional research. Explain why not.