BSIE Probability & Statistics 4

Question 1

Which nonparametric test is the rank-based alternative to the two-sample t-test?

Accepted Answer

Mann-Whitney U test

Answer

The Mann-Whitney U test (also called Wilcoxon rank-sum test) compares two independent groups without assuming normality.

Question 2

If a 90% confidence interval is (18, 26), which conclusion is correct?

Accepted Answer

We are 90% confident the population mean lies between 18 and 26

Answer

A confidence interval means that 90% of such intervals constructed from repeated samples would contain the true population mean.

Question 3

The F-distribution is primarily used in which statistical procedure?

Accepted Answer

Analysis of Variance (ANOVA)

Answer

ANOVA uses the F-statistic (ratio of between-group to within-group variance) to compare three or more group means.

Question 4

In simple linear regression y = β₀ + β₁x + ε, what does β₁ represent?

Accepted Answer

Average change in y for a one-unit increase in x

Answer

β₁ is the slope, representing the expected change in the response variable y per unit increase in the predictor x.

Question 5

A quality engineer takes samples of size n = 25 from a process with σ = 10. What is the standard error of the sample mean?

Accepted Answer

2.0

Answer

Standard error = σ / √n = 10 / √25 = 10 / 5 = 2.0.

BSIE - Bachelor of Science in Industrial Engineering Practice Test