My assistant analyzed national gas prices in dollars per gallon. Her summary included this 95% confidence interval estimate of the true population mean gas price per gallon: (3.5512, 3.6688), where the format is from Minitab where the first number is the lower confidence limit and the second is the upper confidence limit. She already knew the population standard deviation was $0.21 per gallon. From this information, answer these problems:
a. What was her point estimate of the true population mean gas price per gallon? Round your answer to 2 decimal places and include the proper units with your numerical answer, using ONE word following your numerical answer and do not use a symbol.
b. What was her margin of error [also called the maximum error of the estimate]? Round your answer to 4 decimal places and include the proper units with your numerical answer, using ONE word following your numerical answer and do not use a symbol.
c. What was her standard error or the standard deviation of the sample mean distribution? Round your answer to 2 decimal places and include the proper units with your numerical answer, using ONE word following your numerical answer and do not use a symbol.
d. What was her sample size? Report your answer as an integer.