Asimple random sample of 48 adults is obtained from a normally distributed population, and each person's red blood cell count (in cells per microliter) is measured. the sample mean is 5.23 and the sample standard deviation is 0.56. use a 0.01 significance level and the given calculator display to 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. what do the results suggest about the sample group?