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.

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.

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.

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.

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.

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.

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.

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.