I.

The expected number of miles constructed in a day is $$5*0.6 + 2*0.3 + 1*0.1 = 3.7$$ miles.

II.

The variance of daily highway mileage is given by $$5^2*0.6 + 2^2*0.3 + 1^2*0.1 - (3.7)^2 \\ = 16.3 - 13.69 \approx 2.61$$, implying a standard deviation of approximately $$1.62$$ miles.

III.

It would be typical for the workers to lay 10 miles of highway in one day based on the calculated mean and variability.

Which of the above statements is/are true?