Certified Quality Technician Questions Flashcards

Which type of sampling selects every nth item from a production process?

Answer: Systematic sampling

Systematic sampling selects items at regular intervals (every nth unit) from an ordered population or production stream.

What does the 'Operating Characteristic (OC) curve' in acceptance sampling show?

Answer: The probability of accepting a lot at various quality levels

The OC curve plots the probability of acceptance against the incoming lot quality (fraction defective), showing how well a sampling plan discriminates between good and bad lots.

Which of the following is a measure of central tendency?

Answer: Median

The median is a measure of central tendency representing the middle value in an ordered data set.

An X-bar and R chart shows a run of 8 consecutive points above the centerline. This is an indication of:

Answer: A special cause of variation

Eight or more consecutive points on one side of the centerline is a standard Western Electric rule violation, indicating a special (assignable) cause of variation.

In quality cost reporting, the cost of inspecting incoming raw materials is categorized as:

Answer: Appraisal cost

Incoming inspection is an appraisal activity because it evaluates product quality rather than preventing defects or dealing with failures.

What is the primary purpose of a check sheet in quality control?

Answer: To systematically collect and organize data in real time

A check sheet is a structured form for collecting and organizing data in real time at the location where the data is generated.

The probability that a system with two independent components in parallel will fail is:

Answer: P(A) × P(B)

For two independent components in parallel, the system fails only when BOTH fail, so P(system failure) = P(A fails) × P(B fails).