Hello, this question is from H7 Spring 2017 Solutions (Indiana University, Purdue University Indianapolis)(ECON E470), a document on your website. It provides a solution but I cannot figure out where they are getting their numbers. I tried asking for an explanation through the document itself but your team failed to provide one. I am honestly super disappointed in this website as this is usually the case when I ask questions on here or they are answered completely wrong. Please change my mind and don't make me unsubscribe before my subscription even ends..

15 Perform the following test of hypothesis: Ho: 66 5 65 H1: 66 > 65 The t-Stat for the test is, 4.212 4.955 5.829 6.858 t-Stat = (d6 - ds) /se(d6 - ds) var(d6 - ds) = var(ds) + var(d6) - 2cov(ds, d6) = 0.0216 se(d6 - ds) = 0.1469 t-Stat = 6.858 P-value = 7.4E-09 Conclude that DISPAD is more effective than just DISP for increasing sales