Question

The table shows the results of a survey in which separate samples of 400 adults each from the​ East, South,​ Midwest, and West were asked if traffic congestion is a serious problem in their community. Complete parts​ (a) and​ (b).

A table consists of four rows containing the following information from top to bottom, with row listed first and information listed second; row 1, East 35%; row 2, South 33%; row 3, Midwest 28%; row 4, West 57%.EastSouthMidwestWest35%33%28%57%

​(a) Construct a​ 95% confidence interval for the proportion of adults from the

MidwestMidwest

who say traffic congestion is a serious problem.The​ 95% confidence interval for the proportion of adults from the

MidwestMidwest

who say traffic congestion is a serious problem is

​(nothing​,nothing​).

​(Round to three decimal places as​ needed.)

Answer 1

95% confidence interval for Midwest proportion is

- Z * sqrt( ( 1 - ) / n) < p < + Z * sqrt( ( 1 - ) / n)

0.28 - 1.96 * sqrt( 0.28 * 0.72 / 400) < p < 0.28 + 1.96 * sqrt( 0.28 * 0.72 / 400)

0.236 < p < 0.324

95% CI is ( 0.236 , 0.324 )