This problem has been solved! See the answer Determine Um (mode), average U, and Urms for a group of ten automobiles clocked by radar at speeds 38,44,48,50,55,55,57,58 and 60mi/h respectively

The mode is the most common number.

Um = 55

The mean is the sum of the numbers divided by the quantity.

Uavg = (38 + 44 + 45 + 48 + 50 + 55 + 55 + 57 + 58 + 60) / 10

Uavg = 51

The RMS (root mean square) is the square root of the sum of the squares of the numbers divided by the quantity.

Urms = √[ (38² + 44² + 45² + 48² + 50² + 55² + 55² + 57² + 58² + 60²) / 10]

Urms = 51.451