The accompanying data on cube compressive strength

(MPa) of concrete specimens appeared in the article

“Experimental Study of Recycled Rubber-Filled HighStrength Concrete” (Magazine of Concrete Res., 2009:

549–556):

112.3 97.0 92.7 86.0 102.0 99.2 95.8 103.5 89.0 86.7

a. Is it plausible that the compressive strength for this type of concrete is normally distributed?

b. Suppose the concrete will be used for a particular application unless there is strong evidence that true average strength is less than 100 MPa. Should the concrete be used? Carry out a test of appropriate hypotheses using the P-value method.