Question

the average number of red blood cells in an adult male is 6.2 million cells per microliter, with a standard deviation of 0.6 million cells per microliter. if sergeis blood contains 6.7 million cells per microliter, which option correctly calculates and interprets his z - score? (1 point)
sergeis red blood cell count is 0.5 standard deviations above the mean.
sergeis red blood cell count is 0.5 standard deviations below the mean.
sergeis red blood cell count is 0.833 standard deviations above the mean.
sergeis red blood cell count is 0.833 standard deviations below the mean.

Explanation:

Step1: Recall the z - score formula

The z - score formula is \(z=\frac{x - \mu}{\sigma}\), where \(x\) is the data point, \(\mu\) is the mean, and \(\sigma\) is the standard deviation.

Step2: Identify the values

Given \(\mu = 6.2\), \(\sigma=0.6\), and \(x = 6.7\).

Step3: Calculate the z - score

Substitute the values into the formula: \(z=\frac{6.7 - 6.2}{0.6}=\frac{0.5}{0.6}\approx0.833\). Since \(z>0\), it is above the mean.

Answer:

C. Sergei's red blood cell count is \(0.833\) standard deviations above the mean.