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 34%; row 2, South 31%; row 3, Midwest 25%; row 4, West 56%.EastSouthMidwestWest34%31%25%56%

​(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

​(0.2080.208​,0.2920.292​).

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

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

EastEast

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

EastEast

who say traffic congestion is a serious problem is

​(nothing​,nothing​).

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

Answer 1

Answer (B)

Given that proportion for east = 0.34

sample size is n = 400

Using TI 84 calculator

STAT>TESTS>1-PropZInt

x = 0.34*400 = 136

n = 400

c-level = 0.95

Press ENTER, we get

(0.294, 0.386)