Question 596028
Test Statistic:



<img src="http://latex.codecogs.com/png.latex?\LARGE z = \frac{\bar{x}-\mu}{\frac{\sigma}{\sqrt{n}}}" title="x" />



<img src="http://latex.codecogs.com/png.latex?\LARGE z = \frac{6.60-7.3}{\frac{0.50}{\sqrt{40}}}" title="x" />



<img src="http://latex.codecogs.com/png.latex?\LARGE z = \frac{-0.7}{\frac{0.50}{\sqrt{40}}}" title="x" />



<img src="http://latex.codecogs.com/png.latex?\LARGE z = \frac{-0.7}{\frac{0.50}{6.32455532033676}}" title="x" />



<img src="http://latex.codecogs.com/png.latex?\LARGE z = \frac{-0.7}{0.0790569415042}" title="x" />



<img src="http://latex.codecogs.com/png.latex?\LARGE z = -8.85437744847252" title="x" />



So the test statistic is approximately <img src="http://latex.codecogs.com/png.latex?\LARGE z = -8.85437744847252" title="x" />