Question

Suppose you are told that a 95% confidence interval for the average price of a gallon of regular gasoline in your state is from $3.43 to $3.77. Use the fact that the confidence interval for the mean is in the form x − E to x + E to compute the sample mean and the maximal margin of error E. (Round your answers to two decimal places.)

x = $
E = $

Answer 1

Confidence interval can be expressed in terms of - E to + E

So,

- E = 3.43 and + E = 3.77

Add these two equations

2 = 3.43 + 3.77

= 3.6

Put this value of in equation + E = 3.77 and solve for E

3.6 + E = 3.77

E = 0.17

= $3.6

E = $0.17