Identify the symmetrical interval that includes 95% of the sample means for a population with a mean equal to 44 and a standard deviation equal to 9 using a sample size of 36

You’re ordering more thread for blue jeans co. you usually purchase from ted’s threads, which sells 12 thread spools for $27. you recently received a notice from wade's wares that says you can buy thread from them for $2.30 each for the first 2 dozen and $2 a spool thereafter. you need to order 5 dozen spools. what percentage can you save by going with wade’s wares?