The amounts of electricity bills for all households in a city have a skewed probability distribution with a mean of $137 and a standard deviation of $30. Find the probability that the mean amount of...

The amounts of electricity bills for all households in a city have a skewed probability distribution with a mean of $137 and a standard deviation of $30. Find the probability that the mean amount of electric bills for a random sample of 75 households selected from this city will be within $6 of the population mean .