In an experiment to compare bearing strengths of pegs inserted in two different types of mounts, a sample of 14 observations on stress limit for red oak mounts resulted in a sample mean and sample standard deviation of 8.58 MPa and 0.73 MPa, respectively, whereas a sample of 12 observations when Douglas fir mounts were used gave a mean of 9.46 and a standard deviation of 1.58. Consider testing whether or not true average stress limits are identical for the two types of mounts. Compare df's and P-values for the unpooled and pooled t tests.