Arrange the following measurements, in seconds, from the greatest bias to the least bias. 6.63 ± 0.01 s, 6.6 ± 0.1 s, 6.52 ± 0.05 s, 6.4 ± 0.5 s

I understand here "bias" to be the uncertainty of measurements. So the order will be the following:

6.4 ± 0.5 s

6.6 ± 0.1 s,

6.63 ± 0.01 s,

6.52 ± 0.05 s,

(notice how the second number, the one behind the symbol ± gets smaller, as the bias gets smaller).