Whats is the best estimate for a car?

Describe in detail how you would construct a 95% confidence interval for a set of 30 data points whose mean is 20 and population standard deviation is 3. be sure to show that you know the formula and how to plug into it. also, clearly state the margin of error.

Which table shows a proportional relationship between miles traveled and gas used?

Anyone? 15m is what percent of 60m; 3m; 30m; 1.5 km?