z Scores: Red Blood Cell Count Let x 5 red blood cell (RBC) count in millions per cubic millimeter of whole blood. For healthy females, x has an approximately normal distribution with mean m 5 4.8 and standard deviation s 5 0.3 (based on information from Diagnostic Tests with Nursing Implications, edited by S. Loeb, Springhouse Press). Convert each of the following x intervals to z intervals.

(a) 4.5 x

(b) x 4.2

(c) 4.0 x 5.5 Convert each of the following z intervals to x intervals.

(d) z 1.44

(e) 1.28 z

(f) 2.25 z 1.00 (g) Interpretation If a female had an RBC count of 5.9 or higher, would that be considered unusually high? Explain using z values and Figure 6-15.