Table 2.

Accuracy metrics for the indoor algorithm. By difference, we mean the difference between the estimated distance as computed by the app and the reference distance, as measured by the trundle wheel.

Accuracy metric	Value
Mean difference (m)	−2.01
Median difference (m)	−1.51
Standard deviation of the difference (m)	7.84
Correlation	0.99
Mean absolute difference (m)	5.55
Standard deviation of the absolute difference (m)	5.84
Minimum absolute difference (m)	0
Maximum absolute difference (m)	23.68