A. the Weekly Average SO2 Concentration Should Not Exceed 0.04 Ppm

Homework #3

CIVL 7012/8012

Due Wednesday, February 25, 2009

1.  4-56

2.  4-80

3.  4-95

4.  4-110

5.  A foundation engineer estimates that the settlement of a proposed structure will not exceed 2 inches with 95% probability. From a record of performance of many similar structures built on similar soil conditions, he finds that the coefficient of variation of the settlement is about 20%. If a normal distribution is assumed for the settlement of the proposed structure, what is the probability that the proposed structure will settle more than 2.5 inches?

6.  The daily SO2 concentration in the air for a given city is normally distributed with a mean of 0.03 ppm and a coefficient of variation of 40%. Assume statistical independence between the SO2 concentration for any 2 days. Suppose the criteria for clean air standard require that:

a.  The weekly average SO2 concentration should not exceed 0.04 ppm.

b.  The SO2 concentration should not exceed 0.075 ppm on more than 1 day during a given week.

Determine which one of these two criteria is more likely to be violated in this city. Substantiate your answer with calculated probabilities.