SOLVED

21) Natural variations: A) are variations that are to be identified and investigated. B) are variations that can be traced to a specific cause. C) are the same as assignable variations. D) lead to occasional false findings that processes are out of control. E) play no role in statistical process control. 22) Assignable variation: A) is a sign that a process is under control. B) is to be identified and investigated. C) is the same as random variation. D) is variation that cannot be traced to a specific cause. E) leads to a steep OC curve. 23) Assignable causes: A) are not as important as natural causes. B) are within the limits of a control chart. C) depend on the inspector assigned to the job. D) are also referred to as “chance” causes. E) are causes of variation that can be identified and investigated. 24) Control charts for variables are based on data that come from: A) acceptance sampling. B) individual items. C) averages of small samples. D) averages of large samples. E) the entire lot. 25) The purpose of an x-bar chart is to determine whether there has been a: A) change in the dispersion of the process output. B) change in the percent defective in a sample. C) change in the central tendency of the process output. D) change in the number of defects in a sample. E) change in the AOQ. 26) The number of defects after a hotel room cleaning (sheets not straight, smears on mirror, missed debris on carpet, etc) should be measured using what type of control chart? A) x-bar chart B) R-chart C) p-chart D) c-chart E) either x-bar chart or R chart 27) The number of late insurance claim payouts per 100 should be measured with what type of control chart? A) x-bar chart B) R-chart C) p-chart D) c-chart E) either p-chart or c-chart 28) The upper and lower limits for diving ring diameters made by John’s Swimming Co. are 40 and 39 cm., respectively. John took 11 samples with the following average diameters (39, 39.1, 39.2, 39.3, 39.4, 39.5 39.6, 39.7, 39.8, 39.9, 40). Is the process in control? A) Yes, no diameters exceeded the control limits. B) No, some diameters exceeded the control limits. C) No, there is a distinguishable pattern to the samples. D) No, the range is not in control. E) There is not enough information to make a decision. 29) Red Top Cab Company receives multiple complaints per day about driver behavior. Over 9 days the owner recorded the number of calls to be 3, 0, 8, 9, 6, 7, 4, 9, and 8. What is the upper control limit for the 3-sigma c-chart? A) 13.35 B) 8.45 C) 24.00 D) 0.00 E) 9.03 30) A process that is assumed to be in control with limits of 89 ± 2 had sample averages for the x-bar chart of the following: 87.1, 87, 87.2, 89, 90, 88.5, 89.5, and 88. Is the process in control? A) Yes. B) No, one or more averages exceeded the limits. C) Not enough information to tell. D) No, there is a distinguishable trend. E) No, two or more consecutive points are very near the lower (or upper) limit.