CE Mark
CE Mark is a visible declaration by the manufacturer (or his representative, importer, etc.) that the equipment which is marked complies with all the requirements of all the applicable European Union (EU) directives.

CHAID
Chi-square Automatic Interaction Detection is a statistical technique used to segment customers on the basis of multiple alternative variables. The analysis creates a segmentation tree and continues to add different variables (branches), to the tree as long as it is statistically significant.

Characteristic Matrix
An analytical technique for displaying the relationship between process parameters and manufacturing stations.

Check Sheet
A simple data recording device - this helps delineate important items and characteristics to direct attention to them and verify they are evaluated.

Combinatorial Optimization
The efficient allocation of limited resources to yield the best solution to meet the objectives when the values of some or all of the variables must be integers and there are many possible combinations.

Conformance
Means that the material meets the customer's specifications and requirements.

Confounding
allowing two or more variables to vary together so that it is impossible to separate their unique effects. If an experiment does not vary x and y separately then the effects of the two factors cannot be distinguished. Blocking may be used to separate these effects where one is expected to be a critical X and one appears to be noise. The main effects and interactions can be confounded in order to reduce the number of runs in a fractional factorial design of experiments.

Conjoint Analysis
involves measurement of psychological judgments (such as one's preferences) or perceived similarities or differences between alternatives (for example - which factors - price, quality, dealer location - are most important to customers when buying a new car).

Conjoint Measurement
the difference from conjoint analysis is that it permits the use of rating when evaluating pairs of attributes or attribute profiles.