The resilient moduli of 10 samples of a clay mixture are measured and the sample mean is -x = 19.50. If an experimenter wishes to use a "known" value σ = 1.0 for the standard deviation of the resilient modulus measurements based upon prior experience, construct appropriate 90%, 95%, and 99% two-sided confidence intervals for the average resilient modulus μ. Compare the lengths of the confidence intervals. Do you think it is plausible that the average resilient modulus is equal to 20.0?