Statistical Quality Control Mock Test 8

10%

Question 1 of 10

1. The EWMA charts are constructed by plotting _______________ versus the sample number i or the time.

The sample observation, x_i

The variance of variable z_i i.e. \(\sigma_{z_i}^2\)

The variable z_i

The sample variance, σ²

Question 1 of 10

Question 2 of 10

2. Which of these is always correct?

\(C_i^->1.323\)

\(C_i^-≥0 \)

\(C_i^-≤0\)

\(C_i^-<-1.323\)

Question 2 of 10

Question 3 of 10

3. What is the value of EWMS?

\(S_i^2= λ(x_i-μ)^2-(1-λ) S_{i-1}^2\)

\(S_i^2= λ(x_i-μ)^2-(1+λ) S_{i-1}^2\)

\(S_i^2= λ(x_i-μ)^2+(1+λ) S_{i-1}^2\)

\(S_i^2= λ(x_i-μ)^2+(1-λ) S_{i-1}^2\)

Question 3 of 10

Question 4 of 10

4. What is the full form of EWMA?

Exponentially weighted measured approximate

Exponentially weighted measured average

Exponentially weighted moving approximate

Exponentially weighted moving average

Question 4 of 10

Question 5 of 10

5. EWMV is ____________

Exponentially weighted mean variability

Exponentially weighted moving variance

Exponentially weighted mean variance

Exponentially weighted moving variability

Question 5 of 10

Question 6 of 10

6. Combined Cusum-Shewhart procedure is applied _____________

Off-line control

On-line control

On-line measure

Question 6 of 10

Question 7 of 10

7. What is the value of L=2.27 upper control limit for a EWMA chart which has value of λ=0.10 and the value of the standard deviation σ=1 and the value of μ₀=10?

9.59

10.10

10.41

10.27

Question 7 of 10

Question 8 of 10

8. Which of these steps, is not carried out when the process becomes out-of-control when using the cusum control charts?

Taking corrective action

Search for an assignable cause

Continuing the control chart

Restarting the control chart from zero

Question 8 of 10

Question 9 of 10

9. Who did first introduce the EWMA charts?

Roberts (1959)

Crowder (1987a, 1989)

Saccucci (1990)

Lucas (1990)

Question 9 of 10

Question 10 of 10

10. In the case of Shewhart charts, if the data is not according to the normal distribution, the actual in-control ARL (ARL₀) will be ____________ the expected value.

Equal to

Considerably lower than

Almost equal to

Considerably higher than

Question 10 of 10