1. Graphs by Individual Variables

Many quality characteristics can be expressed in terms of numeric values. Measurable quality characteristics such as weight, dimension or volume are called variables.

Example 1:

We will upload data regarding the viscosity of a given product.

Lot	Viscosity	Band
1	33.75
2	33.05	0.70
3	34.00	0.95
4	33.81	0.19
5	33.46	0.35
6	34.02	0.56
7	33.68	0.34
8	33.27	0.41
9	33.49	0.22
10	33.20	0.29
11	33.62	0.42
12	33.00	0.62
13	33.12	0.12
14	34.84	1.72
15	33.79	1.05
16	33.85	0.06
17	34.05	0.20
18	34.02	0.03
19	33.89	0.13
20	34.12	0.23
21	34.10	0.02
22	33.99	0.11
23	34.11	0.12

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Setting as shown in the figure below to perform the analysis

• Click on “Test Options” to decide which tests we will run. In our case, we will select all of them and click OK.

Then click Calculate we obtain the results. You can also generate the analyses and download them in Word format.

The results are:

Individual Values ​​Chart

	Value
Upper Limit	34.817
Center line	33.749
Lower Limit	32.681

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Moving Amplitude Chart

	Value
Upper Limit	1.313
Center line	0.402
Lower Limit	0.000
Standard deviation	0.356

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Points out of control - Individual Values ​​Chart

Subgroups	Value	Test
14	34.84	1 point more than 3 Sigmas from the center line
13	33.12	7 points or more in sequence on the same side of the center line
23	34.11	7 points or more in sequence on the same side of the center line

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Points out of control - Moving Amplitude Chart

Subgroups	Value	Test
14	1.72	1 point more than 3 Sigma from the center line
23	0.12	7 points or more in a row on the same side of the center line
15	1.05	2 of 3 consecutive points greater than 2 deviations pattern from the center line

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Example 2:

Consider the example above, after some changes in production, new viscosity measurements were made. We want to make a comparison between before and after these changes.

Factor	Lot	Viscosity
Before	1	33.75
Before	2	33.05
Before	3	34.00
Before	4	33.81
Before	5	33.46
Before	6	34.02
Before	7	33.68
Before	8	33.27
Before	9	33.49
Before	10	33.20
Before	11	33.62
Before	12	33.00
Before	13	33.12
Before	14	34.84
Before	15	33.79
Before	16	33.85
Before	17	34.05
Before	18	34.02
Before	19	33.89
Before	20	34.12
Before	21	34.10
Before	22	33.99
Before	23	34.11
After	1	33.56
After	2	34.23
After	3	33.82
After	4	33.23
After	5	33.39
After	6	33.70
After	7	33.67
After	8	33.84
After	9	33.81
After	10	33.55
After	11	33.90
After	12	33.69
After	13	33.84
After	14	33.68
After	15	34.20
After	16	33.41
After	17	34.09
After	18	33.42
After	19	33.49
After	20	33.96
After	21	34.16
After	22	33.62
After	23	32.90

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Setting as shown in the figure below to perform the analysis

• Click on “Test Options” to decide which tests we will run. In our case, we will select all of them and click OK.

Then click Calculate we obtain the results. You can also generate the analyses and download them in Word format.

The results are:

Individual ​​Chart

	Before	After
Upper Limit	34.817	34.689
Center line	33.749	33.703
Lower Limit	32.681	32.716

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Moving Range Chart

	Before	After
Upper Limit	1.313	1.212
Center line	0.402	0.371
Lower Limit	0.000	0.000

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Moving Range Chart (Standard Deviation)

	Before	After
Standard Deviation	0.356	0.329

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Out of control points - Individual Values ​​Chart

Subgroups	Value	Factor	Test
14	34.84	Before	1 point greater than 3 Sigmas from the center line
13	33.12	Before	7 points or more in sequence on the same side of the center line
23	34.11	Before	7 points or more in sequence on the same side of the center line

Out of control points - Moving Amplitude Chart

Subgroups	Value	Factor	Test
14	1.72	Before	1 point greater than 3 Sigma from the center line
23	0.12	Before	7 points or more in sequence on the same side of the center line
15	1.05	Before	2 of 3 consecutive points greater than 2 sigmas from the center line
14	0.16	After	7 points or more in sequence on the same side of the center line