Final answer:
The standard error of the estimate cannot be determined from the given regression equation without additional statistical data. The distribution of sample means is expected to be normal for large sample sizes according to the Central Limit Theorem.
Step-by-step explanation:
To determine the value of the standard error of the estimate in a regression equation, we need additional statistical data such as the sum of the squared residuals or the number of observations. Since the question does not provide this necessary information, it is not possible to calculate the standard error of the estimate from the given regression equation (y = 7.6 + .9x) alone.
As for the distribution of the sample mean, in the context of regression analysis and according to the Central Limit Theorem, if the sample size is large enough, the distribution of the sample means will be approximately normally distributed around the actual population mean no matter the shape of the original data distribution.