Step 1 :The margin of error for a confidence interval can be calculated using the formula: \[E = Z \times \frac{\sigma}{\sqrt{n}}\] where: E is the margin of error, Z is the Z-score, which corresponds to the desired confidence level (for a 95% confidence level, Z = 1.96), \(\sigma\) is the standard deviation of the population, and n is the size of the sample.
Step 2 :In this case, we know that \(\sigma = 1000\), \(n = 78\), and \(Z = 1.96\). We can substitute these values into the formula to find the margin of error.
Step 3 :Calculate the margin of error: \[E = 1.96 \times \frac{1000}{\sqrt{78}}\]
Step 4 :The calculated margin of error is approximately 221.92629869234074.
Step 5 :Round the margin of error to the nearest whole number: \[\text{round}(E) = 222\]
Step 6 :Final Answer: The margin of error for the mean at the 95% confidence level, rounded to the nearest whole number, is \(\boxed{222}\).