Deep mixing is a ground improvement method developed for soft soils like clay, s
ID: 3052510 • Letter: D
Question
Deep mixing is a ground improvement method developed for soft soils like clay, silt, and peat. Civil engineers investigated the properties of soil improved by deep mixing with lime-cement columns. The mixed soil was tested by advancing a cylindrical rod with a cone tip down into the soi. During penetration, the cone penetrometer measures the cone tip resistance (megapascals, MPa). The researchers established that tip resistance for the deep mixed soil followed a normal distribution with = 1.9 MPa and = 0.8 MPa. Complete parts a through c. a. Find the probability that the tip resistance will fall between 1.3 and 4.0 MPa P(1.3sxS4.0)(Round to four decimal places as needed.) Enter vour answer in the answer box and then click Check Answer 2Explanation / Answer
Ans:
Given that
mean=1.9
standard deviation=0.8
z(1.3)=(1.3-1.9)/0.8=-0.75
z(4)=(4-1.9)/0.8=2.625
P(-0.75<z<2.625)=P(z<2.625)-P(z<-0.75)
=0.9957-0.2266=0.7690