12 points By-Hand) The table below gives the print times (in hours) of two brands of 3-D printers using patterns for five different items on each printer. Because different item atterns could affect print times differently, the two 3-D printer brands will be compared for each item (i.e., the print times are matched together by item). Note that the em patterns were randomly selected and assigned, and all data appears to be approximately normally distributed. Item A Item B Item C Item E Item F Print-o-matic You-print 3.98 2.40 3.23 3.73 1.89 4.72 4.03 4.55 3.42 2.38 a) Using the appropriate six-step testing procedure, is there sufficient evidence at the a = 0.01 significance level to conclude that the difference in mean print time for the Print-o-matic device is smaller than that of the You-print device? b) Based upon your conclusion, either present and interpret a 98% confidence interval for the actual mean difference or explain why the test results indicate that a confidence interval is not necessary. Upload a single PDF of your complete solution to this By-Hand exercise in the box below. Previous Drag n' Drop here or Browse MacBook Pro Next (By-Hand) An engineer measured the hardness of a random sample of metal alloy from a production plant, and if the mean hardness exceeds (is greater than) 168, then the product will be rejected. The SPSS output from her analysis appears below. Expected Normal Value Normal Q-Q Plot of Density, 190 180 170 160 150 150 160 170 Observed Value 180 190