Confidence Intervals

Confidence intervals help assess accuracy and quantify uncertainty in results from sampled datasets. When querying sum or count fields on adaptive datasets, you can request a confidence interval to understand the possible range around an estimate. For example, specifying a confidence level of 0.95 returns the estimate, along with the range of values that likely contains the true value 95% of the time.

• Supported datasets: Adaptive (sampled) datasets only.
• Supported fields: All sum and count fields.
• Usage: Confidence level must be provided as a decimal between 0 and 1 (for example,0.90, 0.95, 0.99).
• Default: If no confidence level is specified, intervals are not returned.

The following example shows how to query a confidence interval and interpret the response.

To request a confidence interval, use the confidence(level: X) argument in your query.

query SingleDatasetWithConfidence($zoneTag: string, $start: Time, $end: Time) {
  viewer {
    zones(filter: {zoneTag: $zoneTag}) {
      firewallEventsAdaptiveGroups(
        filter: {datetime_gt: $start, datetime_lt: $end}
        limit: 1000
      ) {
        count
        avg {
          sampleInterval
        }
        confidence(level: 0.95) {
          count {
            estimate
            lower
            upper
            sampleSize
          }
        }
      }
    }
  }
}

The response includes the following values:

• estimate: The estimated value, based on sampled data.
• lower: The lower bound of the confidence interval.
• sampleSize: The number of sampled data points used to calculate the estimate.
• upper: The upper bound of the confidence interval.

In this example, the interpretation of the response is that, based on a sample of 40,054, the estimated number of events is 42,939, with 95% confidence that the true value lies between 42,673 and 43,204.

{
  "data": {
    "viewer": {
      "zones": [
        {
          "firewallEventsAdaptiveGroups": [
            {
              "avg": {
                "sampleInterval": 1.0720277625205972
              },
              "confidence": {
                "count": {
                  "estimate": 42939,
                  "lower": 42673.44115335711,
                  "sampleSize": 40054,
                  "upper": 43204.55884664289
                }
              },
              "count": 42939
            }
          ]
        }
      ]
    }
  },
  "errors": null
}