Question

1. A factory located in an urban neighborhood is causing controversy. Some people protest the factory’s harmful environmental emissions. Others point to job opportunities that the factory provides for community members. A local community organization surveys a random sample of 200 residents of the neighborhood and finds that 43% of the respondents agree with a statement calling for the factory to close.

1. What is the 99% confidence interval for π, the population proportion of neighborhood residents who agree that the factory should close?

2. Based on your findings, is it safe to say that the majority of the neighborhood’s residents want the factory to close? Why or why not?

Answer 1

a)

99% confidence interval is

- Z/2 * sqrt [ ( 1 - ) / n ] < p < + Z/2 * sqrt [ ( 1 - ) / n ]

0.43 - 2.576 * sqrt [ 0.43 ( 1 - 0.43) / 200] < p < 0.43 + 2.576 * sqrt [ 0.43 ( 1 - 0.43) / 200]

0.340 < p < 0.520

99% CI is ( 0.340 , 0.520 )

b)

Since 0.50 contained in confidence interval, and some values in interval are less than 0.50

It is not safe to say that the majority of the neighborhood’s residents want the factory to close