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Assuming that the large sample sizes mean that your course permits the use of the z-statistic in the calculation of the confidence interval, then the limits are:
Lower limit = -3.6221
Upper limit = 0.0221
If the above assumption is not correct, then the t-statistic must be used, and the limits are:
Lower limit = -3.6382
Upper limit = 0.0382
Please feel free to ask if you have any questions about this solution.
Since it seemed that you only need the values, I used my calculator to calculate the interval limits.
If you need to do a calculation by hand, I can type up. It will only take a few minutes.
Here is the work for calculating the limits of the interval:
Clicking the above link will take you to a page where you can download the solutions as a Word document. Please let me know if you have any difficulty accessing this file.
Please feel free to ask if you have any additional questions about this.