WEAKNESSES

One of the weaknesses of my study was that it was conducted over only a portion of the year, so really its results should probably be applied only to the time period during which I did my study, March to May.  Also, the weather could have had a large effect, since less people probably go shopping while the weather is bad.  Also, for my study I only counted the number of people entering the store, and not the number actually making purchases.

EXTRAPOLATION

I would feel confident about extrapolating my results to all grocery stores in Northeastern Ohio that are open during the time periods I used.  I would only extrapolate it to Northeastern Ohio because over a long distance the climate and population of an area can change, which could affect the times during which people do grocery shopping.  However, I would not extrapolate my results to the days around major holidays like Christmas or Thanksgiving, because Easter was included during my study and I noticed that on the days preceding Easter the data varied greatly from the rest of the days.

SUGGESTIONS

I would suggest a yearlong study of this test to confirm that the time of year would not affect the times when people go to the grocery store.  Also, I would suggest that tests be done in different areas to remove that as an extraneous factor.  One might also want to consider selecting several stores at which to do this study rather than just one like I did.