Answer:
B. 1.70
Step-by-step explanation:
Given:
[tex]\textsf{If }\: X \sim\textsf{N}(\mu,\sigma^2)\:\textsf{ then }\: \overline{X} \sim \left(\mu,\dfrac{\sigma^2}{n}\right) \implies Z=\dfrac{\overline{X}-\mu}{\sigma / \sqrt{n}} \sim \textsf{N}(0,1)[/tex]
[tex]\textsf{then test statistic is}: \quad z=\dfrac{\overline{x}-\mu}{\sigma / \sqrt{n}}[/tex]
Substituting the given values into the formula to find the test statistic z:
[tex]\begin{aligned}\implies z &=\dfrac{65.1-60}{24 / \sqrt{64}}\\\\&=\dfrac{5.1}{3}\\\\&=\dfrac{17}{10}\\\\&=1.7\end{aligned}[/tex]
