Currently Live: JEE Mains 2025 Session 2
Select your session to view predictions and statistics:
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Across Sessions Confidence Interval and Margin of Error
| Session | Responses | Margin of Error (%) | Confidence Interval Width (%) |
|---|---|---|---|
| Cumulative Responses | 0 | ||
How Accurate Are the Predictions?
Our rank predictions are based on statistical sampling and become more accurate as more people submit their data. To understand this, let's break down three important concepts:
Confidence Level
The confidence level represents how certain we are that the true value lies within our predicted range. A 99% confidence level means that if we repeated this prediction process many times, the true rank would fall inside the predicted interval 99 out of 100 times.
Mathematically, we use a z-score corresponding to the confidence level. For 99% confidence:
z = 2.576
Margin of Error
The margin of error (MOE) tells us how far off our prediction could be from the true value due to sampling variability.
It is calculated as: MOE = z * sqrt[ p(1-p)/n ] * sqrt[ (N-n)/(N-1) ]
where:
zis the z-score (2.576 for 99% confidence),pis the estimated proportion (assumed 0.5 for max variability),nis the number of samples (responses submitted),Nis the total JEE candidate population per session (assumed ~100,000).
Confidence Interval
The confidence interval is the range within which we expect the true rank to lie.
It's computed as:Prediction ± MOE