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The sample size is relatively large (say, n > 10— ¯ and R charts are typically used for smaller sample sizes) The sample size is variable; Computers can be used to ease the burden of calculation; The "chart" actually consists of a pair of charts: One to monitor the process standard deviation and another to monitor the process mean, as is ...
The sample size is relatively small (say, n ≤ 10— ¯ and s charts are typically used for larger sample sizes) The sample size is constant; Humans must perform the calculations for the chart; As with the ¯ and s and individuals control charts, the ¯ chart is only valid if the within-sample variability is constant. [4]
PICK charts are a method to prioritize a number of action items or problem solving ideas. A pick chart allows visual comparison of action items relative to their impact to the problem being addressed vs. the ease/cost of implementation. In VERY rudimentary terms, PICK charts are a Return On Investment (ROI) method.
The value 3.267 is taken from the sample size-specific D 4 anti-biasing constant for n=2, as given in most textbooks on statistical process control (see, for example, Montgomery [2]: 725 ). Calculation of individuals control limits
The table shown on the right can be used in a two-sample t-test to estimate the sample sizes of an experimental group and a control group that are of equal size, that is, the total number of individuals in the trial is twice that of the number given, and the desired significance level is 0.05. [4]
The global priorities, shown in black, are obtained by multiplying the local priorities of the siblings by their parent's global priority. The global priorities for all the subcriteria in the level add up to 1.000. The rule is this: Within a hierarchy, the global priorities of child nodes always add up to the global priority of their parent.
Control charts are graphical plots used in production control to determine whether quality and manufacturing processes are being controlled under stable conditions. (ISO 7870-1) [1] The hourly status is arranged on the graph, and the occurrence of abnormalities is judged based on the presence of data that differs from the conventional trend or deviates from the control limit line.
The X-bar chart is always used in conjunction with a variation chart such as the ¯ and R chart or ¯ and s chart. The R-chart shows sample ranges (difference between the largest and the smallest values in the sample), while the s-chart shows the samples' standard deviation. The R-chart was preferred in times when calculations were performed ...