According to the question:
Time taken to cover the distance = 2.00 ns
= 2.00 x 10-9 s
Speed of light = 3.0 x 108 ms-1
Distance travelled by light in 2.00 ns
= Speed of light x Time taken
= (3.0 x 108 ms-1)(2.00 x 10-9 s)
= 6.00 x 10-1 m
= 0.600 m
Find the mean deviation about the mean for the data 38, 70, 48, 40, 42, 55, 63, 46, 54, 44.