A simple random sample of 50 adults is obtained, and each person’s red blood cell count (in cells per microliter) is measured. The sample mean is 5.23 cells/μL. The population standard deviation for red blood cell counts is 0.54 cell/μL. Test the claim that the sample is from a population with a mean less than 5.4 cells/μL, which is a value often used for the upper limit of the range of normal values. 

What do the results suggest about the sample group?