In this chapter, we talk about the continuous variable control chart.

I-MR Chart

The I-MR is a control chart for continue variable, where the data are get from sample of size of 1 or 2. In image1 you can look an example of data for this contorl chart.

Image1 - data
Image1 – data

The moving range is the distance from the attribute xi and the xi-1. In addition, we have two couple of control limits and a mean because this control chart is based on two charts. These two charts work together.

In image2 you can look at the formula.

image2 - Imr formula
image2 – Imr formula

The data like D4, D3, and E2 are the constant that you can find on google searching for a control chart stable table. Finally, in the image3, you can look at the control chart plotted in excel.

image3 - Imr chart
image3 – Imr chart

Xbar-S Chart

The Xbar-S is a control chart for continue variable, where the data are get from sample of size > 10. In image4 you can look an example of data for this contorl chart.

Image4 - data
Image4 – data

Look that:

  • For every sample, we have ten measurements;
  • XBar is the mean of every sample;
  • Mean X Bar is the mean of the all X Bar;
  • STD S is the man of every sample;
  • Mean S is the mean of the STD.

In addition, we have two couple of control limits and a mean because this control chart is based on two charts. These two charts work together.

In image5 you can look at the formula.

image5 - Xbars formula
image5 – Xbars formula

The data like A3, B4, and B3 are the constant that you can find on google searching for a control chart stable table. They are different for diffferent sample size. Finally, in the image6, you can look at the control chart plotted in excel.

image6 - XbarS chart
image6 – XbarS chart

Xbar-R Chart

The Xbar-r is a control chart for continue variable, where the data are get from sample of size from 3 to 9. In image7 you can look an example of data for this contorl chart.

Image7 - data
Image7 – data

Look that:

  • For every sample, we have four measurements;
  • XBar is the mean of every sample;
  • Mean X Bar is the mean of the all X Bar;
  • Range R is the distance from the min and the max of the sample;
  • Mean R is the mean of all the range.

In addition, we have two couple of control limits and a mean because this control chart is based on two charts. These two charts work together.

In image8 you can look at the formula.

image8 - XbarR formula
image8 – XbarR formula

The data like A2, D3, and D4 are the constant that you can find on google searching for a control chart stable table. They are different for diffferent sample size. Finally, in the image9, you can look at the control chart plotted in excel.

image9 - XbarR chart
image9 – XbarR chart
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