QUESTION 3 Polymer composite materials have gained popularity because they have high strength to weight ratios and are relatively easy and inexpensive to manufacture. However, their nondegradable nature has prompted development of environmentally friendly composites using natural materials. An article reported that for a sample of 10 specimens with 2% fiber content, the sample mean tensile strength (MPa) was 51.6 and the sample standard deviation was 1.2. Suppose the true average strength for 0% fibers (pure cellulose) is known to be 48 MPa. Do the data provide compelling evidence for concluding that true average strength for the WSF/cellulose composite exceeds this value? What is the value of the test statistic for this test? Round to three decimal places as necessary. QUESTION 4 The article "Uncertainty Estimation in Railway Track Life-Cycle Cost"t presented the following data on time to repair (min) a rail break in the high rail on a curved track of a certain railway line. 159 120 480 149 270 547 340 43 228 202 240 218 Assume that the data follow an approximate normal distribution. Is there compelling evidence for concluding that true average repair time exceeds 200 min? What is the p-value for this test? Round to three decimal places as necessary