Question

3. A telephone company wants to estimate the porportion of households that would purchase an additional service line if it were made available at a substantially reduced cost. A random sample of 500 households is selected and the results indicate that 135 of the households would purchase the additional service. Construct and explain a 99% confidence interval estimate of the proportion of all households that would purchase the additional service.

Answer 1

Example of a proportional confidence interval formula:

CI99 = p + or - (2.58)[√(pq/n)]
...where p = x/n, q = 1 - p, and n = sample size.
Note: + or - 2.58 represents 99% confidence interval.

For p in your problem: 135/500 = 0.27
For q: 1 - p = 1 - 0.27 = 0.73
n = 500

I let you take it from here to calculate the interval.

Answer 2

For those of us who don't understand, you didn't help.