The article "Measurement of Complex Permittivity of Asphalt Paving Materials" (J. Shang, J. Umana, et al., Journal of Transportation Engineering, 1999:347– 356) compared the dielectric constants between two types of asphalt, HL3 and HL8, commonly used in pavements. For 42 specimens of HL3 asphalt the average dielectric constant was 5.92 with a standard deviation of 0.15, and for 37 specimens of HL8 asphalt the Navidi-3810214 book November 11, 2013 14:8 432 CHAPTER 6 Hypothesis Testing average dielectric constant was 6.05 with a standard deviation of 0.16. Can you conclude that the mean dielectric constant differs between the two types of asphalt?