ASQ Certified Manager of Quality / Organizational Excellence (CMQ/OE) — Question 22

A shop floor technician has recorded the following data:
Machine 1 has an average of 12.6 inches for 10 samples.
Machine 2 has an average of 12.5 inches for 20 samples.
The samples taken from these two machines can be compared in which of the following ways, if any?

Answer options

• A. They are statistically the same parts.
• B. They are statistically different parts.
• C. They cannot be compared because they have used different sample sizes.
• D. They cannot be compared without knowing the standard deviations of the samples.

Correct answer: C

Explanation

The correct answer is C because comparing averages from different sample sizes can lead to misleading conclusions about their similarity. While knowing standard deviations provides more context, the difference in sample sizes alone makes a direct comparison invalid.