The residential energy consumption survey found in 2001 that 47% of american household had internet access. a market survey organization repeated this study in a certain town with 25,000 households, using a simple random sample of 500 households: 239 of the same households had internet access.

a) the percentage of households in the town with internet access is estimated at ; this is likely to be off by or so.

b) if possible, find a 95%-confidence interval for the percentage of all 25,000 households with internet access. if this is not possible, explain why or why not.