Develop a 95 percent confidence interval for the difference in total crime rates between public and private schools.

I have a confidence interval calcuator but not 100% sure on what goes in each bucket in order for it to calculate.

Data I have:

Sum of total crime at private schools: 1404 Sum of total crime at public schools: 1397 Total: 2801

# of private schools: 67 # of public schools: 99

Total: 166

Am I right to say we are using the population standard deviation is known?

Sample mean: ____? Population standard deviation (sigma): ____?

Sample Size (n): I assume this would be total schools surveyed so 166?

Confidence Level: .95 (95%)

Picture of calcualtor and I'm seeking an understanding of what goes in each one, and why. Just giving #'s won't earn points. Giving links won't earn points. Thank you :)