# How to create a six pack in minitab

### What is Capability Sixpack?

Minitab’s

**Capability Sixpack**allows you to assess the**capability**of a process at a glance by combining the following quality tools into a single display: · Xbar or Individuals charts to determine whether the process is in control. If the process in out of control, the**capability**indices are invalid.### What is the subgroup size in Minitab?

A

**subgroup**is simply a group of units produced under the same set of conditions. Ideally, it is a set of measurements taken close together in time, yet still independent of each other. In our case, the lightsabers were measured by a different Jedi each day for 10 days, with 8 sabers being measured by each.### What is a capability plot?

What is a DP

**capability plot**? DP**capability plot**is a crucial tool developed to assess vessel ability to keep position and heading under certain environmental conditions. Based on a vessel design we estimate external forces caused by wind, waves and current for every angle of attack.### What is a good process capability?

Cpk = or >1.33 indicates that the

**process**is capable and meets specification limits. Any value less than this may mean variation is too wide compared to the specification or the**process**average is away from the target.### Is a process capable?

**Process Capability**(Cp) is a statistical measurement of a

**process’s**ability to produce parts within specified limits on a consistent basis. Cp tells you if your

**process**is

**capable**of making parts within specifications and Cpk tells you if your

**process**is centered between the specification limits.

### What if CP is less than 1?

By convention, when the Cpk is

**less than one**, the process is referred to as incapable. When the Cpk is greater**than**or equal to**one**, the process is considered capable of producing a product within specification limits. The Cpk index can never be greater**than**the**Cp**, only equal to it.### What is CP CPK?

**Cp and Cpk**, commonly referred to as process capability indices, are used to define the ability of a process to produce a product that meets requirements. Specifications: Specifications define product requirements. In other words, they define what is expected from an item for it to be usable.

### How many Sigma is 1.67 Cpk?

Sigma level table

Two sided table | ||
---|---|---|

Cpk Ppk |
Sigma level |
PPM out of tolerance |

1.33 | 4.0 | 63.342 |

1.50 | 4.5 | 6.795 |

1.67 |
5.0 | 0.573 |

### What is a good CP and CPK?

In general, the higher the

**Cpk**, the better. A**Cpk**value less than 1.0 is considered poor and the process is not capable. A value between 1.0 and 1.33 is considered barely capable, and a value greater than 1.33 is considered capable. But, you should aim for a**Cpk**value of 2.00 or higher where possible.### What is a good CPK?

The higher the

**Cpk**, the better is the capability of the process to meet its requirements. In the industry, a**Cpk**of less than 1.66 needs a closer look. A**Cpk**that’s less than 1.33 needs some action to make it higher, and a**Cpk**of less than 1.0 means that the process is not capable of meeting its requirements.### What is min in CPK formula?

The

**formula**for the**calculation**of**Cpk**is**Cpk**=**min**(USL – μ, μ – LSL) / (3σ) where USL and LSL are the upper and lower specification limits, respectively. A process with a**Cpk**of 2.0 is considered excellent, while one with a**Cpk**of 1.33 is considered adequate.### What does a Cpk of 1 mean?

If a process is perfectly centered, it has a Cp of

**1**. That would indicate that**mean**was 3 standard deviations away from the upper limit and the lower limit. A perfectly centered process – a process who has a**mean**exactly in between the 2 specification limits (**meaning**halfway between the two will have a**Cpk of 1**.### What is the highest Cpk value?

The minimum

**value**of “k” is 0 and the**maximum**is 1.0. A perfectly centered process will have Cp =**Cpk**.### Why is PPK higher than CPK?

The automotive confusion aside,

**Ppk**will always be**greater than Cpk**since**Ppk**is long term capabliity and**Cpk**is short term capability. The only way that**Cpk**will be**greater than Ppk**(other**than**a misuse of the terms and formulas) is under the conditions stated in a previous post.### What does a Cpk of 0 mean?

The

**CPk**=**0**when the**mean**is exactly on the specification limit, so**does**the**Cpk**have a negative value ? Presumably, the**Cpk**value will be negative when the**mean**is outside the spec limits.### Can CPK be negative?

**Can Cpk**or Ppk be

**Negative**? Yes, it is possible for

**Cpk**and Ppk to be

**negative**. Let’s look at the equation – for simplicity we will use the Ppk. It is impossible to have a standard deviation be

**negative**so that would mean that x(bar) was larger that the Specification Limit.

### What is negative CPK?

A

**negative Cpk**value**means**the average is outside of the spec range.### What is a good CPK and PPK?

When the

**Cpk**calculation is a high number (general industry guideline is 1.66 or higher), then it is a**good**indication the process is statistically in control. If the**Cpk and Ppk**calculations are very close or equal, then there is an even better indication that the process is statically in control.### What is a good CPK and PPK value?

For stable processes and normally distributed data, a

**Cpk value**≥ 1.33 should be achieved. For chronically unstable processes with output meeting specification and a predictable pattern, a**Ppk value**≥ 1.67 should be achieved.”### What does CPK 1.67 mean?

This

**means**that, for the control limit that is closer to the specification limit (be it the upper or lower control limits), the distance between the process average and that specification limit is at least**1.67**times the distance between the process average and that control limit.### Why PPK is lower than CPK?

If we look at the formulas for

**Cpk**and**Ppk**for normal (distribution) process capability, we can see they are nearly identical: The only difference lies in the denominator for the Upper and**Lower**statistics:**Cpk**is calculated using the WITHIN standard deviation, while**Ppk**uses the OVERALL standard deviation.