The thicknesses of eight pads designed for use in aircraft engine mounts are measured. The results, in mm, are 41.83, 41.01, 42.68, 41.37, 41.83, 40.50, 41.70, and 41.42. Assume that the thicknesses are a sample from an approximately symmetric distribution.

a. Can you conclude that the mean thickness is greater than 41 mm? Compute the appropriate test statistic and find the P-value.

b. Can you conclude that the mean thickness is less than 41.8 mm? Compute the appropriate test statistic and find the P-value.

c. The target thickness is 42 mm. Can you conclude that the mean thickness differs from the target value? Compute the appropriate test statistic and find the P-value.(a) The signed ranks are