Your average weekly grocery bill at the store you usually shop is $300. You decided to test a new strategy of buying most items over the weekend from Costco in bulk and when you fall short of some items during the week or the once not appropriate for Costco, you buy from a convenience store near you. You took a sample of your expenses for 20 weeks and found that the average is $285 and the standard deviation for the sample is $25. Set up your null and alternative hypothesis for testing whether your cists are different and do the analysis using α=.05.