The dynamic modulus of concrete is obtained for two different concrete mixes. For the first mix, \(n_{1}=33\), \(\bar{x}=115.1\), and \(s_{1}=0.47\) psi. For the second mix, \(n_{2}=31, \bar{y}=114.6\), and \(s_{2}=0.38\). Test, with \(\alpha=0.05\), the null hypothesis of equality of mean dynamic modulus versus the two-sided alternative.