1. This problemwhich is a basic TWO population means comparison hypothesis test (NOT a proportion problem - so we use t-values, not z-values). SHOW t-TEST SETUP and calculation, AND for the t-Critical, what SIGNIFICANCE LEVEL (the column) and what df (which row)were used and what the t-Critical value is.

Do people avoid driving on Friday the 13^th ?Here are data on 20 Fridays:10 on the 13^th and the other 10 on the Friday before.Calculate the MEAN difference and SD between traffic on these two Fridays at the 95% level;

Traffic Count Dates 6th (x1 ) 13th (x2) d = (x1 - x2) 1990, July 139246 138548 1990, July 138012 132908 1991, September 137055 136018 1991, September 140675 131843 1991, December 123552 121641 1991, December 121139 120723 1992, March 128293 125532 1992, March 124631 120249 1992, November 124609 125770 1992, November 119584 116263 For the differences (all d's) the MEAN = and the SD =