ASQ Certified Quality Inspector & Reliability Engineer 4

Question 1

When constructing an X-bar and R chart with a subgroup size of 5, which constant is used to calculate the upper control limit for the R chart?

Accepted Answer

D4

Answer

UCL_R = D4 × R-bar, where D4 is the control chart constant for the upper range limit at n=5 (D4 = 2.114).

Question 2

Which document formally specifies the characteristics that a product must possess to be considered acceptable?

Accepted Answer

Product specification

Answer

A product specification defines all required characteristics, dimensions, materials, and performance requirements a product must meet.

Question 3

The Weibull distribution is widely used in reliability engineering because it can model:

Accepted Answer

All three phases of the bathtub curve depending on the shape parameter β

Answer

The Weibull shape parameter β < 1 models burn-in, β = 1 models random failures, and β > 1 models wear-out, making it extremely versatile.

Question 4

In a hypothesis test, a quality engineer sets α = 0.05. This means:

Accepted Answer

There is a 5% probability of rejecting the null hypothesis when it is actually true

Answer

The significance level α is the probability of a Type I error — concluding a difference exists when the null hypothesis is actually true.

Question 5

A quality inspector uses GO/NO-GO gauges primarily to:

Accepted Answer

Verify a part conforms to upper and lower specification limits

Answer

GO/NO-GO gauges quickly verify whether a feature falls within its tolerance limits without providing a variable measurement.

ASQ - American Society for Quality Certification Practice Test