BSE Engineering Statistics and Data-Driven Decision Making 2

Question 1

A 95% confidence interval for the mean diameter of a part is (49.8 mm, 50.2 mm). Which interpretation is correct?

Accepted Answer

If the procedure were repeated many times, 95% of such intervals would contain the true mean

Answer

95% of all parts have diameters between 49.8 and 50.2 mm

Answer

There is a 95% probability the true population mean is between 49.8 and 50.2 mm

Answer

The sample mean will fall in this interval 95% of the time

Question 2

In statistical process control, a process is said to be 'in control' when:

Accepted Answer

Only common cause variation is present

Answer

All output meets customer specifications

Answer

Special cause variation is detected and removed

Answer

Cp and Cpk are both greater than 2.0

Question 3

An engineer computes a p-value of 0.03 in a hypothesis test with a significance level of α = 0.05. The correct conclusion is:

Accepted Answer

Reject H₀ because 0.03 < 0.05

Answer

Fail to reject H₀ because 0.03 < 0.05

Answer

Fail to reject H₀ because the difference is not practical

Answer

Accept H₀ because the p-value is small

Question 4

Which of the following is a nonparametric alternative to the one-sample t-test?

Accepted Answer

Wilcoxon signed-rank test

Answer

F-test

Answer

Chi-square goodness-of-fit test

Answer

Two-proportion z-test

Question 5

Process capability index Cpk is different from Cp because Cpk:

Accepted Answer

Accounts for process centering relative to specification limits

Answer

Uses the range instead of standard deviation

Answer

Only applies to one-sided specifications

Answer

Measures long-term capability rather than short-term

Question 6

In a multiple regression model, multicollinearity refers to:

Accepted Answer

High correlation among independent predictor variables

Answer

Non-linear relationships between predictor and response variables

Answer

Unequal variance of residuals across fitted values

Answer

Autocorrelation in the residuals over time

Question 7

Which data visualization technique is best suited for identifying the primary causes of a quality problem using the 80/20 rule?

Accepted Answer

Pareto chart

Answer

Scatter diagram

Answer

Histogram

Answer

Control chart