The sample average unrestrained compressive strength UCS for

The sample average unrestrained compressive strength (UCS) for 45 specimens of a particular type of brick was computed to be 3142 psi. and the sample distribution of UCS may be somewhat skewed Does the the data strongly indicate that the true average UCS is less than the design value of 3200? If the observed z statistic were -1.76 (which it is not), then the p-value for this test would be:

Solution

Z = -1.76

so using tables of normal distribution we will find the p value and that is

0.039