Discuss the issues of statistical significance and practical importance in each scenario.
a. A process for producing I-beams of oriented strand board used as main support beams in new houses has a mean breaking strength of 2,000 lbs./ft. A sample of boards from a new process has a mean breaking strength of 2,150 lbs./ft. The improvement is statistically significant, but the per-unit cost is higher.
b. Under continuous use, the mean battery life in a certain cell phone is 45 hours. In tests of a new type of battery, the sample mean battery life is 46 hours. The improvement is statistically significant, but the new battery costs more to produce.
c. For a wide-screen HDTV LCD unit, the mean half-life (i.e., to lose 50 percent of its brightness) is 32,000 hours. A new process is developed. In tests of the new display, the sample mean half-life is 35,000 hours. The improvement is statistically significant, though the new process is more costly.