Browse Glossary  
V W X Y Z #
The Complete Lean Shop
Glossary - N

N - The number of units in a population.

n -
The number of units in a sample.

Nagara System -
Smooth production flow, ideally one piece at a time, characterized by synchronization (balancing) of production processes and maximum use of available time; includes overlapping of operations where practical. A nagara production system is one in which seemingly unrelated tasks can be produced simultaneously by the same operator.

Institute of Standards and Technology (NIST) - An agency of the U.S. Department of Commerce that develops and promotes measurements, standards and technology, and manages the Malcolm Baldrige National Quality Award.

Natural Team -
A team of individuals drawn from a single work group; similar to a process improvement team except that it is not cross functional in composition and it is usually permanent.

Natural Work Groups
- A term used to describe teams that are organized according to a common product, customer, or service.

Negatively Skewed Distribution - A distribution of data where most of the data appears on the right hand side of the distribution and then tails off to the left. Also known as a skewed left distribution.

Networking - Developing relationships with other individuals for the purpose of sharing ideas, providing support and unifying efforts.

New Philosophy
- May have several meanings, but is usually a reference to the relatively recent emphasis on quality and the management principles that must accompany it. In some cases it is meant as a reference to Deming's theory for management.

New Seven Tools
aka N7
(1) Managerial tools that are used in quality improvement.
(2) In addition to the seven tools there are "newer" tqm tools that are recommended for problem-solving or planning. Some of these are: affinity diagram, force field analysis, cross-impact matrix, ripple-effect diagram or wheel, planning tree diagram, five "whys?", The data-collection checksheet, and the process-conformance checklist.

Next Operation as Customer -
The concept of internal customers in which every operation is both a receiver and a provider.

Nine Dots
- A reference to the puzzle in which nine dots (three rows of three, equally spaced) are to be connected by four straight lines. Solutions require that one go "outside" the imagined box delineated by the perimeter of the dots...A difficult task for most people because they are conditioned by their training and experience. The message intended by this reference is that it is often important to get "outside" our paradigms or our typical way of viewing a situation or a problem.

Nominal Group Technique -
(1) A technique, similar to brainstorming, to generate ideas on a particular subject. Team members are asked to silently write down as many ideas as possible. Each member is then asked to share one idea, which is recorded. After all the ideas are recorded, they are discussed and prioritized by the group. (2) To use a group’s expertise to select from among options. With a team and when there are no or limited data to help select an option or a solution to a problem. This technique is only as good as the skills and knowledge of the team that it using it. (3) A weighted ranking technique used by teams or small groups to narrow down a list of items.

Nominal Value
- The stated "target" value for a characteristic of the outcome of a process...As distinguished from what the process is delivering.

Non Value Added -
A term that describes a process step or function that is not required for the direct achievement of process output. This step or function is identified and examined for potential elimination. Also see “value added.”

- State that exists when a product, service, or material does not conform to the customer requirements or specifications.

Nonconforming - Nonconforming data is a count of defective units. It is often described as go/no go, pass/fail, or yes/no, since there are only two possible outcomes to any given check. You can track either the number of defective units or the number of nondefective units.

Nonconformities - Nonconformities data is a count of defects per unit or group of units. It can refer to defects or occurrences that should not be present but are, or any characteristic that should be present but is not.

Nonconforming Unit
- A unit which does not conform to stated requirements/specification.

- A condition within a unit which does not conform to some specific specification/ requirement. Also commonly called a defect. Any given nonconforming unit can have the potential for more than one nonconformity. OR the nonfulfillment of a specified requirement. Also see “blemish,” “defect” and “imperfection.”

Nondestructive Testing and Evaluation (NDT, NDE) -
Testing and evaluation methods that do not damage or destroy the product being tested.

Nonlinear Parameter Estimation -
A method whereby the arduous and labor intensive task of multiparameter model calibration can be carried out automatically under the control of a computer.

Nonnormal Data - Data that does not form a normal distribution.

Nonnormal Data Distribution - Any data set that does not show a normal, bell-shaped distribution.

Nonparametric Tests -
All tests involving ranked data (data that can be put in order). Nonparametric tests are often used in place of their parametric counterparts when certain assumptions about the underlying population are questionable. For example, when comparing two independent samples, the Wilcoxon Mann-Whitney test (see listing) does not assume that the difference between the samples is normally distributed, whereas its parametric counterpart, the two-sample t-test, does. Nonparametric tests can be, and often are, more powerful in detecting population differences when certain assumptions are not satisfied.

Nonrandom Pattern - A pattern in data that is repeating, or is not due to normal variation.

Nonrandom Variation -
 Controllable variation.

Non-Value-Adding -
Any process or event that does not make a product more like what a customer is willing to pay for. Lean Manufacturing is almost completely about removing waste from manufacturing and processes. Waste is best defined as "any process that does not add value to a product." Value-Adding activities are any activity that makes a product more like what a customer is willing to pay for. 

Norm (behavioral) -
Expectations of how a person or persons will behave in a given situation based on established protocols, rules of conduct or accepted social practices.

Normal Curve
- (1) The familiar Normal Distribution "bell curve". The mathematical expression for the normal curve is y = (2π)-_e-x2/2. The normal curve is symmetric around the point x=0, and positive for every value of x. The area under the normal curve is unity, and the sd of the normal curve, suitably defined, is also unity. (2) This bell-shaped curve is used to illustrate the shape of a normal distribution.

Normal Distribution
- (1) A pattern of variation of a continuous variable continuous variable characterized by a symmetric bell-shaped curve. (2) A data distribution that is bell shaped and symmetrical, the normal distribution is the basis for control chart and capability analysis. (3) Normal distribution is the spread of information (such as product performance or demographics) where the most frequently occurring value is in the middle of the range and other probabilities tail off symmetrically in both directions. Normal distribution is graphically categorized by a bell-shaped curve, also known as a Gaussian distribution. For normally distributed data, the mean and median are very close and may be identical.

Normal distribution (statistical) -
The charting of a data set in which most of the data points are concentrated around the average (mean), thus forming a bell shaped curve.

Normal Probability Plot - A normal probability plot is a graphical method for showing a frequency distribution. The scaling is set up so that if the distribution is normal, a straight line will result.

Normality - When a population has a statistically normal distribution.

Normality Tests
- Tests of whether a set of data is distributed in a way that is consistent with a normal distribution.

- The third stage of team development, where the team becomes a cohesive unit, and interdependence, trust, and cooperation are built.

Np Chart
- (1) A chart used to monitor the number of items defective for a fixed sample size. (2) An attributes control chart that plots the number of items that are defective or possess a characteristic of interest. The subgroup size must remain constant for this type of chart to be used.

Null Hypothesis - In hypothesis testing, the hypothesis we wish to falsify on the basis of the data. The null hypothesis is typically that something is not present, that there is no effect, or that there is no difference between treatment and control.

Number of affected units chart -
A control chart for evaluating the stability of a process in terms of the total number of units in a sample in which an event of a given classification occurs.