A manufacturer claims that the average tensile strength of thread A exceeds the average tensile strength of thread B by at least 12 kilograms. To test this claim, 50 pieces of each type of thread were tested under similar conditions. Type A thread had an average tensile strength of 86.7 kilograms with a standard deviation of 6.28 kilograms, while type B thread had an average tensile strength of 77.8 kilograms with a standard deviation of 5.61 kilograms. Test the manufacturer’s claim using a 0.05 level of significance. 1. Determine the Z calculated in two decimal places. 2. Determine the Z table in two decimal places. 3. Is the manufacturing claim statistically valid? yes or no

Question

A manufacturer claims that the average tensile strength of thread A exceeds the average tensile

strength of thread B by at least 12 kilograms. To test this claim, 50 pieces of each type of thread were tested

under similar conditions. Type A thread had an average tensile strength of 86.7 kilograms with a standard

deviation of 6.28 kilograms, while type B thread had an average tensile strength of 77.8 kilograms with a

standard deviation of 5.61 kilograms. Test the manufacturer’s claim using a 0.05 level of significance. 1. Determine the Z calculated in two decimal places. 2. Determine the Z table in two decimal places. 3. Is the manufacturing claim statistically valid? yes or no