Answer to Question #228035 in Statistics and Probability for NDUME

Question

Suppose a sample of 200 local vendors is selected as part of a survey conducted by the Ministry of Trade and it is found that 145 of the local vendors make an average income in excess of N$ 7 600 per month. 

A).What is the 98% confidence interval estimate of the population proportion of local vendors who make an average income in excess of N$ 7 600 per month?

B).Suppose that a 97% confidence interval estimate of the proportion of local vendors who make an average income less than N$ 7 600 per month is required. How large a sample should be taken if the desired margin of error is 5%?

C). Suppose it has been established from past studies that 75% of local vendors make an average income in excess of N$ 7 600 per month. Use the p-value approach and conduct a hypothesis test at a 1% level of significance to determine whether the proportion of local vendors who make an average income in excess of N$ 7 600 per month differs from the historical level. Show all hypothesis test steps.