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. The population standard deviation for red blood cell counts is 0.54. At the 5% significance level, test the claim that the sample is from a population with a mean less than 5.4, which is a value often used for the upper limit of the range of normal values.