To understand your competitive position, you have examined the reliability of your product as well as the reliability of your closest competitor’s product. You have subjected each product to abuse that represents about a year’s worth of wear-and-tear per day. Table 10.7.7 shows the data indicating how long each item lasted.

a. Find the average time to failure for your and your competitor’s products. Find the average difference (yours minus your competitor’s).

b. Find the appropriate standard error for this average difference. In particular, is this a paired or an unpaired situation? Why?

c. Find the two-sided 99% confidence interval for the mean difference in reliability.

d. Test at the 1% level if there is a significant difference in reliability between your products and your competitor’s.

e. Find the p-value for the difference in reliability (as either p > 0.05, p < 0.05, p < 0.01, or p < 0.001).

f. Write a brief paragraph, complete with footnote(s), that might be used in an advertising brochure showing off your products.

TABLE 10.7.7 Days until Failure Your Products Competitor's 0.2 2.8 8.9 1.2 10.3 4.9 3.1 3.6 2.1 2.9 8.6 5.3 7.2 2.2 2.5 2.6 2.0 0.5 2.3 1.2 6.6 0.5 1.2