Question:
Safety engineers at a manufacturing plant are evaluating two brands of 50-ampere electrical fuses for possible purchase and use in the plant. One of the performance characteristics they are considering is how long the fuse will carry 50 amperes before it blows. In a sample of 35 fuses from the Shockley Fuse Company, the mean time was found to be 240 milliseconds, with a standard deviation of 50 milliseconds. In comparable tests of a sample of 30 fuses from the Fusemaster Corporation, the mean time was 221 milliseconds, with a standard deviation of 28 milliseconds. Using the 0.10 level of significance, examine whether the population mean times for fuses from the two companies might be the same. What is the most accurate statement that could be made about the p-value for this test? Construct and interpret the 90% confidence interval for the difference between the population means. Is the hypothesized difference (0.00) within the interval? Given the presence or absence of the 0.00 value within the interval, is this consistent with the findings of the hypothesis test?