intro practice · coding problem
Summarize a small dataset
Latency samples (ms): 12, 14, 15, 16, 200. Compute mean, median, and sample standard deviation. Which summary is misleading for SLA reporting and why?
The mechanism
Descriptive stats compress a dataset into a few numbers you can reason about. Mean chases outliers; median resists them. Correlation measures linear co-movement, not causation — and breaks under nonlinearity.
Expected evidence
Mean ≈ 51.4 (pulled by outlier), median = 15 (robust), std dev is large. Report median + p95 for SLAs, not mean.
Try this drill in the practice workspace →
Hints when you need them
- Sort for median.
- One outlier dominates the mean.
Watch for these mistakes
- Using mean on heavy-tailed latency data
- Treating correlation as causation
- Reporting precision without sample size