Help with my geometry please

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.

List x1, x2, x3, x4 where xi is the midpoint endpoint of the five equal intervals used to estimate the area under the curve of f(x) between x = 0 and x = 10.

Ken leaves work 20 minutes late. he decides to make up time by taking the toll road instead of side streets. he can travel three times faster by taking the toll road. create an equation to represent his total travel time, including wait time, where x is the number of minutes the drive was expected to take