A cartridge company develops for a printer company and supplies both the ink and the cartridges. The company is interested in the number of cartridges used over the life of the printer. A sample of 149 printers is selected, and from the data a sample mean of 6 and a sample standard deviation of 0.88 cartridges was calculated. Find the best point estimate for 0.2 The proportion of calls to an emergency hotline answered within 5 seconds is of importance. A sample of 1,737 calls yielded a proportion of 0.64 calls in 5 seconds. Assume that calls are independent and that they follow a Binomial distribution. What is the best point estimate for the population proportion of calls? l Arsenic concentration in public drinking water supplies is a potential health risk. An article reported drinking water arsenic concentrations in parts per billion (ppb) for 15 metropolitan communities in Phoenix and 15 communities in rural Arizona. The sample yielded means of 10.1 and 33.7, respectively. What is the best point estimate for the mean difference in arsenic concentration? Two different types of polishing solution are being evaluated for possible use in a tumble-polish operation for manufacturing interocular lenses used in the human eye following cataract surgery. 346 lenses were tumble-polished using the rst polishing solution, and of this number 293 had no polishing-induced defects. Another 346 lenses were tumble-polished using the second polishing solution, and 188 lenses were satisfactory on completion. What is the best point estimate for the difference in proportion of the two polishing solutions? The thickness of a particular material is of interest to researchers. A random sample of 702 random samples of the material are measured and thicknesses recorded in centimeters. A sample mean was found to be 77.7 centimeters. What is the best point estimate for I4