Data Collection & Analysis Methods Flashcards

A quality team wants to track the frequency of defect types over a two-week period. Which data collection tool is MOST appropriate?

Answer: Check sheet

A check sheet is a structured form for collecting and tabulating data about defect frequencies over time.

In a histogram, what does a bimodal distribution (two peaks) most likely indicate?

Answer: Two distinct populations or process shifts

A bimodal histogram typically indicates two distinct subpopulations or process conditions mixed in the data.

Which of the following BEST describes stratification as a data analysis technique?

Answer: Separating data into subgroups to identify patterns

Stratification divides data into subgroups (e.g., by shift, machine, or operator) to reveal hidden patterns or causes.

A Pareto chart is based on which underlying principle?

Answer: A vital few categories account for most of the problems

The Pareto principle states that roughly 80% of problems come from 20% of causes, guiding focus on the vital few.

When constructing a scatter diagram, what does a data point cluster along a positive diagonal indicate?

Answer: A positive correlation between variables

Points clustering along a positive diagonal show that as one variable increases, the other tends to increase as well.

Which sampling method ensures every member of a population has an equal chance of being selected?

Answer: Simple random sampling

Simple random sampling gives every unit an equal and independent probability of selection, eliminating selection bias.

A run chart shows seven consecutive data points all above the centerline. What does this pattern signal?

Answer: A potential special cause or process shift

Seven or more consecutive points on one side of the centerline is a run rule indicating a likely special cause.