Think about the validity issues that must be considered when using an experimental design. If your birthday falls in the months of Jan-Mar, give an example of a historical effect on validity and what you could do to mitigate it in a study. If your birthday falls in the months of Jan-Mar, give an example of a historical effect on validity and what you could do to mitigate it in a study. If your birthday falls in the months of Jan-Mar, give an example of a historical effect on validity and what you could do to mitigate it in a study. If your birthday falls in the months of Jan-Mar, give an example of a historical effect on validity and what you could do to mitigate it in a study.