Quality control runs on a PCO₂ electrode have produced a mean of 40 mm Hg ± 2 mm Hg (1 SD).What are the chances of obtaining a value of 45 mm Hg on a control run if the electrode is functioning properly? A) 95% B) 50% C) 5% D) Less than 1%

Question

Quizplus · Accepted Answer

The probability of obtaining a value of 45 mm Hg is calculated using the z-score formula:

z = (x - μ) / σ

where x is the desired value (45 mm Hg), μ is the mean (40 mm Hg), and σ is the standard deviation (2 mm Hg).

z = (45 - 40) / 2 = 2.5

Looking up the z-score in a standard normal distribution table, we find that the probability of getting a value greater than 45 mm Hg is only 0.0062, or less than 1%. Therefore, choice C is the correct answer.

Quality Control Runs on a PCO2 Electrode Have Produced a Mean

Quality Control Runs on a PCO₂ Electrode Have Produced a Mean