ITPEC FE Morning October 2019 Question 77

A chart to see whether a relationship, pattern or trend exists between two numeric attributes — that is a scatter diagram.

Each item measured gives a pair of values, one read on the horizontal axis and one on the vertical, and is plotted as a point. If the points rise together, fall together or form no pattern, the two attributes are positively correlated, negatively correlated or unrelated, for example oven temperature against defect rate.

Answer (a)

Why not others:

• •(b) — summarizing the frequency distribution of one attribute is a histogram
• •(c) — bars in descending order with a cumulative-total line is a Pareto chart
• •(d) — plotting a characteristic over time to judge whether a process is stable is a control chart

Key rule: A scatter diagram relates two variables; a histogram shows the distribution of one, a control chart follows one over time, and a Pareto chart ranks categories.

Corporate Activities · AI-written, may contain errors