The U$.$S$.$ Dairy Industry wants to estimate the mean yearly milk consumption. A sample of $26$ people reveals the mean yearly consumption to be $84$ gallons with a standard deviation of $26$ gallons. Assume the population distribution is normal.

c$.$ What is the margin of error? $($Round your answer to $3$ decimal places.$)$

d$.$ Develop the $95\%$ confidence interval for the population mean. $($Round your answer to $3$ decimal places.$)$