Using the simultaneous testing method, if you get readings of 8.1 pCi/L and 6.9 pCi/L, what is the relative percent difference?

To calculate the relative percent difference between two readings, you first determine the absolute difference between the two values. In this case, the values are 8.1 pCi/L and 6.9 pCi/L. The absolute difference is found by subtracting the lower value from the higher value:

8.1 pCi/L - 6.9 pCi/L = 1.2 pCi/L.

Next, you take the absolute difference and divide it by the average of the two values. The average is calculated by adding the two readings together and dividing by 2:

(8.1 + 6.9) / 2 = 7.5 pCi/L.

Now, you take the absolute difference (1.2 pCi/L) and divide it by the average (7.5 pCi/L):

1.2 / 7.5 = 0.16.

To express this as a percentage, you multiply by 100:

0.16 * 100 = 16%.

This results in a relative percent difference of 16%. Using this method helps ensure that the comparison between readings takes into account the magnitudes of both values relative to their average, which is crucial in a field like radon measurement