Mean and Standard Deviation of a Discrete Variable

The table below shows the probability distribution for the number of miles of highway constructed per day, which varies with the weather.

Consider the following statements.

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 the daily highway mileage is $5^2*0.6 + 2^2*0.3 + 1^2*0.1 - (3.7)^2 \approx 2.61$, so the standard deviation is approximately $1.62$ miles.

III. An observation of 10 miles of highway constructed in one day would be considered a typical result.

Which of the above statements is/are true?