The explicit formula LaTeX: a_n=-11+4\left(n-1\right)a n = − 11 + 4 ( n − 1 ) represents which of the following sequences?

Can you draw an isosceles triangle with only one 80 degree angle?

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.

Extra points! find the missing dimension! need asap