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Unformatted text preview: Chapter 10 Problems 1. Specifications for a part for a DVD player state that the part should weigh between 24 and 25 ounces. The process that produces the parts yields a mean of 24.5 ounces and a standard deviation of .2 ounce. The distribution of output is normal. a. What percentage of parts will not meet the weight specs? Z = 2524.5 / (.2) = 2.5 specs: 24 oz. to 25 oz. = 24.5 oz. [assume = ] = .2 oz. a. [refers to population] (Two tails of 0.0062 probability) b. Within what values will 95.44 percent of sample means of this process fall, if samples of n=16 are taken and the process is in control (random)? 2. An automatic filling machine is used to fill 1liter bottles of cola. The machines output is approximately normal with a mean of 1.0 liter and a standard deviation of .01 liter. Output is monitored using means of samples of 25 observations. a. Determine upper and lower control limits that will include roughly 97 percent of the sample means when the process is in control. = 1.0 liter = .01 liter n = 25 a. [z = 2.17 for 97%] b. Given these sample means: 1.005, 1.001, .998, 1.002, .995, and .999, is the process in control? No, the process is not in control. 4. Computer upgrades have a nominal time of 80 minutes. Samples of five observations each have been taken, and the results are as listed, Using factors from Table 10.3, determine upper and lower control limits for mean and range charts, and decide if the process is in control. SAMPLE 1 2 3 4 5 79.2 80.5 79.6 78.9 80.5 78.8 78.7 79.6 79.4 79.6 80.0 81.0 80.4 79.7 80.4 78.4 80.4 80.3 79.4 80.8 81.0 80.1 80.8 80.6 78.8 Solver  R Enter data i Target 79.9600 Average Range 1.8667 Sample Size 5 LCL Factor, R LCL, R chart UCL Factor, R 2.114 UCL, R chart CL Factor, Xbar 0.577 LCL, Xbar chart Sample 1 2 1 79.2 78.8 80 2 80.5 78.7 81 3 79.6 79.6 80.4 4 78.9 79.4 79.7 5 80.5 79.6 80.4 6 79.7 80.6 80.5 7 Solver  R and XBa The Rchart is in control, so the xbar chart is valid. The xbar chart is also in control.The xbar chart is also in control....
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 Spring '11
 Schneider
 Standard Deviation, Control Chart, LCL

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