Which control chart will look for the control for the dispersion?

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JKSSB JE Mechanical 02 Nov 2021 Shift 1 Official Paper

Answer 1

Explanation:

P-chart:

P-Charts are used for data that is counted. Each data point is a ratio of its own discrete sample set.
P-Charts can display fraction nonconforming or percent nonconforming data values.
The statistical principles used in calculating the UCL (upper critical limit) and LCL (lower critical limit) are based on the binomial distribution.

C-chart:

C-Charts display the number of non-conforming or conforming items within a consistent unit size or the probability of a specific number of occurrences in a specific period of time.
The statistical principles used in calculating the UCL and LCL are based on the Poisson distribution.

X-bar chart:

It indicates how the average or mean changes over time. It's utilized to monitor the process mean when calculating subgroups at regular intervals from a process.
The statistical principles used in calculating the UCL and LCL are based on the normal distribution.

R chart:

It indicates how the range of the subgroups changes over time. This is utilized to monitor process variability, like the range, when measuring subgroups of less than ten at regular intervals in a process. Each point on a chart represents the subgroup range value.
It takes range or dispersion into account for process capability.
The sample size shall be greater than 1 and less than 11. For a larger sample size, an S-chart shall be used.