The formula for the mean and standard deviation of a sampling distribution is
[tex]\begin{gathered} \mu_{\bar{x}}=\mu \\ and\text{ } \\ \sigma_{\bar{x}}=\frac{\sigma}{\sqrt{n}} \end{gathered}[/tex]
Now, on putting the values we have
[tex]\begin{gathered} \sigma=10\text{ and }\mu=126 \\ Then,\text{ } \\ (i).\text{ n=26} \\ \begin{equation*} \mu_{\bar{x}}=126 \end{equation*} \\ and \\ \sigma_{\bar{x}}=\frac{10}{\sqrt{26}} \\ (\imaginaryI\imaginaryI)\text{ n = 38} \\ \begin{equation*} \mu_{\bar{x}}=126 \end{equation*} \\ and \\ \sigma_{\bar{x}}=\frac{10}{\sqrt{38}} \end{gathered}[/tex]
Hence, this is the required answer.
