An 80% confidence interval is 150, 170 what is the margin of error

Complete the solution of the equation. find the value of y when x equals -5. -4x - 8y = -52

Answer pls man im trying to get out of summer school

Astudent must have an average on five test that is greater than it equal to 80% but less than 90% to receive a final grade of b. devon's greades on the first four test were 78% 62% 91% and 80% what range if grades on the fifth test would give him a b in the course? ( assuming the highest grade is 100%)