Click to see additional instructions 19. A random sample of 50 provides a sample mean of 31 with a standard deviation of S =14. The upper bound of a 90% confidence interval estimate of the population mean is26. A manufacturer of computer disks took samples of 240 disks on 15 consecutive days. The number of disks with bad sectors was determined for each of these samples. The results are in the table that follows. Day Bad % Bad 1 9 0.037500 2 7 0.029167 3 4 0.016667 4 6 0.025000 5 8 0.033333 6 3 0.012500 7 6 0.025000 8 10 0.041667 9 16 0.066667 10 24 0.100000 11 15 0.062500 12 9 0.037500 13 4 0.016667 14 8 0.033333 15 6 0.025000 Focusing on the % bad, the appropriate control chart is the ':| chart