In a sample of 41 U.S. adults aged 18-24 who celebrate Halloween, the mean amount spent on a costume was $43.1 with a standard deviation of $14.75. a) What parameter are we estimating? - 0" b) We can work this problem because: - o" c) What is the point estimate of that parameter? - 0' d) What is the standard deviation of the sampling distribution for the sample means? C] e) Find the margin of error for a 95% confidence interval for the true average amount spent on a costume. Use your T-table to do this and round to the fourth C] f) Round to the fourth. We are 95% confident that the true average amount spent on a Halloween costume for U.S. adults aged 18-24 is between 4:] and 5:]