In 2017, Americans spent a record-high $9.1 billion on Hailoween-related purehases (the balance website). Sample dato showing the amount, in dollars, 16 adults spent on a Halloween costume are as follows. a. What is the estimate of the population mean amount adults spend on a Halloween costume (to 2 decimals)? b. What is the sample stondard deviation (to 2 decimals)? c. Provide a 95% confidence interval estimate of the population standard deviation for the amount adults spend on a Hatioween costume (to 2 decimals). Use. Table 11.1. \( 3 \longdiv { 1 } \leq s \) "Noter A more eutenwive table in pecivided an Table 2 of dppendan B (molable onlne)