# Block 9 — Statistical Test Planning for the F-47 ANS

<p class="block-meta"><span class="b-block">Block 09</span><span class="b-time">~30 min</span><span class="b-demos">no demos</span></p>

<p class="block-synopsis">The math underpinning the project: correlation time and effective sample size, the 95th-percentile ECDF for accuracy requirements, drift-slope confidence intervals, peak-and-snapback inference of detection time, and the 27/30 compliance rule.</p>

## What you'll learn

1. Explain why correlated time-series data require **effective sample size** $N_{\text{eff}}$, not the raw sample count $N$.
2. Estimate $T_{\text{corr}}$ from an autocorrelation function and apply the **10% rule of thumb**.
3. Derive $N_{\text{eff}}$ from first principles and plan a statistically defensible test duration.
4. Apply the **95th-percentile ECDF** for accuracy requirements (rather than a CI on the mean).
5. Estimate inertial **drift rate** with a 95% confidence interval on the slope.
6. Infer **fault detection time** from navigation-error behavior when no internal fault flag is available.

## In this block

<div class="block-toc">
  <a class="bt-card bt-reading" href="L09_Project_Reading.html">
    <span class="bt-kind">Reading</span>
    <h4>Reading</h4>
    <p>Effective sample size, 95th-percentile ECDF, drift CIs, and the 27/30 rule.</p>
  </a>
  <a class="bt-card bt-flashcards" href="L09_Flashcards.html">
    <span class="bt-kind">Flashcards</span>
    <h4>Flashcards</h4>
    <p>Click-to-reveal cards for the block's key terms and equations.</p>
  </a>
</div>

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