NP Chart

An NP chart is a type of control chart used in quality control for monitoring the number of defective items in a sample when the sample size remains constant. It is based on the binomial distribution and is similar to the p-chart, but it plots the count (N) of defectives directly.
See also: p-Chart, Control Charts

N (Population Size)

The symbol N typically denotes the total number of items or individuals in the entire population under study. It represents the complete set from which samples may be drawn.
See also: Sampling, Census

n (Sample Size)

The symbol n represents the number of observations or items included in a sample drawn from the population (N). It is used in statistical calculations and inference to estimate population parameters.
See also: Sampling, Statistical Inference

Nagara System

The Nagara system is a production planning and scheduling approach often associated with lean manufacturing principles. It emphasizes synchronizing workflow and balancing production lines so that the entire system operates efficiently, similar in spirit to other just-in-time (JIT) and Kanban systems.
See also: Toyota Production System, Lean Manufacturing, Kanban

Negative Binomial Distribution

The negative binomial distribution is a discrete probability distribution that models the number of failures that occur in a sequence of independent Bernoulli trials before a predetermined number of successes is achieved. It is often used when data exhibit overdispersion relative to the Poisson distribution.
See also: Geometric Distribution, Overdispersion

Nemawashi

Nemawashi is a Japanese term meaning "laying the groundwork." In a business or organizational context, it refers to the process of informally discussing and consulting with stakeholders before a formal decision is made. This practice helps build consensus and smooth the implementation of changes.
See also: Consensus Building, Change Management

Net Present Value (NPV)

Net Present Value (NPV) is a capital budgeting technique used to assess the profitability of an investment or project. It is calculated by discounting all future cash inflows and outflows to their present values and then subtracting the initial investment. A positive NPV indicates that the projected earnings (in present dollars) exceed the anticipated costs.
See also: Discounted Cash Flow, Investment Appraisal

Nominal Group Technique (NGT)

The Nominal Group Technique (NGT) is a structured method for group brainstorming and decision making. Each participant independently generates ideas which are then shared with the group. After a round of discussion, ideas are ranked or voted on, ensuring balanced participation and minimizing the influence of dominant personalities.
See also: Brainstorming, Group Decision Making

Nonconformance

Nonconformance refers to any deviation from specified requirements, standards, or procedures regarding a product, process, or service. It indicates that a particular aspect does not meet established criteria, often triggering corrective actions.
See also: Nonconformity, Corrective Action

Nonconforming Record (NCR)

A Nonconforming Record (NCR) is a documented record that details an instance of nonconformance. It typically includes information about the discrepancy, its impact, and any corrective or preventive actions taken to address the issue.
See also: Nonconformance, Quality Documentation

Nonconformity

Nonconformity is the condition where a product, process, or system fails to meet specified standards or requirements. This term is used interchangeably with nonconformance in many quality management contexts and highlights areas needing correction or improvement.
See also: Nonconformance, Corrective Action

Non-Destructive Testing (NDT)

Non-destructive testing (NDT) comprises techniques used to examine materials, components, or assemblies without causing damage. These methods—such as ultrasonic testing, radiography, magnetic particle testing, and dye penetrant inspection—allow for the detection of internal or surface defects while preserving the item’s serviceability.
See also: Quality Control, Inspection Methods

Non-Parametric Test

A non-parametric test is a statistical test that does not assume the data come from a distribution of a specific form (for example, a normal distribution). These tests are particularly useful when sample sizes are small or when the data do not meet the assumptions required for parametric tests.
See also: Mann-Whitney U Test, Wilcoxon Signed-Rank Test

Non-Value-Added Activities

Non-value-added activities are steps or tasks within a process that consume resources (time, money, effort) without adding any benefit from the perspective of the customer. In lean manufacturing and process improvement, these activities are identified and reduced or eliminated to streamline operations.
See also: Waste Elimination, Lean Principles

Normal Distribution

The normal distribution is a continuous probability distribution that is symmetric and bell-shaped. Defined by its mean and standard deviation, it is one of the most commonly used distributions in statistics and underpins many statistical methods and tests.
See also: Gaussian Distribution, Central Limit Theorem

NPV (Net Present Value)

Refer to the definition provided above for Net Present Value.