The accompanying data in the table below were derived from life tests for two different brands of cutting tools. Complete parts a through c. a Click the icon to view the data table of cutting speed and useful life. 5 Click the icon to View the table of critical values of t. a. Use a 90% condence interval to estimate the mean useful life of a brand A cutting tool when the cutting speed is 45 meters per minute. Repeat for brand B. Compare the widths of the two intervals and comment on the reasons for any difference. The mean useful life of a brand A cutting tool when the cutting speed is 45 meters per minute is to hours. (Round to one decimal place as needed.) 0 Data Table Cutting Speed Useful Life (Hours) \"$35" Brand A Brand 3 30 4.8 6.2 30 4.2 6.3 30 4.6 5.1 40 4.8 5.0 40 4.3 4.8 40 2.5 5.0 50 4.4 4.5 50 2.8 4.0 50 1.0 3.7 60 4.0 3.8 60 2.0 3.0 60 1.1 2.4 70 1.1 1.5 70 0.5 2.0 70 3.0 1.0 Print Done Enter your answer in the edit fields and then click Check Answer. Critical Values of t 0 Degrees of Freedom 1.025 1.005 1.001 1.0005 3.078 6.314 12.706 31.821 1.886 63.657 318.31 2.920 4.303 636.62 6.965 9.925 1.638 2.353 22.326 31.598 3.182 4.541 5.841 1.533 10.213 2.132 12.924 2.776 3.747 4.604 1.476 2.015 7.173 2.571 8.610 3.365 4.032 1.440 1.943 5.893 6.869 2.447 3.143 3.707 1.415 5.208 1.895 5.959 2.365 2.998 3.499 1.397 1.860 4.785 2.306 5.408 2.896 3.355 1.383 4.501 5.041 1.833 2.262 2.821 3.250 1.372 4.297 1.812 4.781 2.228 2.764 1.363 3.169 1.796 4.144 2.201 4.587 2.718 1.356 3.106 4.025 1.782 2.179 4.437 2.681 3.055 1.350 3.930 1.771 4.318 2.160 2.650 3.012 1.345 3.852 1.761 4.221 2.145 2.624 2.977 1.341 3.787 1.753 4.140 2.131 2.602 2.947 1.337 3.733 1.746 4.073 2.120 2.583 2.921 1.333 3.686 1.740 4.015 2.110 2.567 2.898 1.330 3.646 1.734 2.101 3.965 2.552 2.878 1.328 3.610 1.729 2.093 3.922 2.539 2.861 1.325 3.579 1.725 3.883 2.086 2.528 2.845 1.323 3.552 1.721 3.850 2.080 2.518 2.831 1.321 3.527 3.819 1.717 2.074 2.508 2.819 1.319 3.505 1.714 2.069 3.792 2.500 2.807 1.318 3.485 1.711 2.064 3.767 2.492 2.797 1.316 3.467 1.708 3.745 2.060 2.485 2.787 1.315 3.450 1.706 2.056 3.725 2.479 2.779 anca 3.435 2 172 3.707 a con