Module 10 Self-Test

A: Regardless of the underlying distribution, sample means approach a normal distribution as sample size increases, with mean = population mean and SD = σ/√n.

A: SE = 20/√64 = 2.5. CI = 100 ± 1.96 × 2.5 = 100 ± 4.9 = (95.1, 104.9)

A: If you repeated the experiment 100 times, ~95 of the resulting intervals would contain the true value. NOT "95% probability the true value is in this interval."

A: EXISTS for large tables/correlated subqueries (stops at first match). IN for small static value lists.

A: A subquery that references the outer query, re-executing for each outer row.

A: Too high → overshoots, oscillates, may diverge. Too low → very slow convergence.

A: Streaming — fraud detection needs millisecond response times.