Question

Companies that provide environmental cleanup for hazardous waste and toxic chemicals are growing rapidly. W.R. Gross is thinking abot entering this field with a subsidiary called Saf-t-Soil. The wish the estimate the true proportion of U.S. corporation that produce hazardous waste as a by product of their manufacturing process to within 10% with 80% confidence. What sample size will be needed?

Answer 1

Solution :

Given that,

= 0.5

1 - = 1 - 0.5 = 0.5

margin of error = E = 10% = 0.10

At 80% confidence level the z is ,

Z/2 =Z0.1 =1.28 ( Using z table

Sample size = n = (Z/2 / E)2 * * (1 - )

= (1.28 / 0.10)2 * 0.5 * 0.5

= 40.96

Sample size = 41