The average red blood cell count in a young women is assumed to be approximately 4.5 million red cells per cubic millimeter of blood. Red blood cell counts taken on a randomly drawn sample of 12 ECU women athletes yield the data given below. Based on those data, do women athletes appear to have higher red cell counts than the population of women in their age group? Assume that the data in the population are distributed normally; test at the s=0.01 level of significance.

SAMPLE DATA: RED CELL COUNTS/CUBIC ml (in millions): 5.2,4.7,4.3,5.5,4.5,4.5,5.5,4.5,5.3,4.7,5.1,4.8

Is this a two tailed test or one tailed?