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Table 2 Estimated power, sensitivity and positive predictive value (PPV) when the normal scan statistic is used to detect different types of clusters, as described in the text.

From: A scan statistic for continuous data based on the normal probability model

Cluster number Cluster size (%) Sample size Cluster mean Cluster STD Power (%) Sensitivity PPV
Different Cluster Locations
1 10 600 -10% 600 66 0.70 0.74
2 10 600 -10% 600 54 0.56 0.65
3 10 600 -10% 600 64 0.72 0.82
4 10 600 -10% 600 61 0.61 0.64
Different Cluster Size
1 5 600 -10% 600 34 0.52 0.48
1 10 600 -10% 600 66 0.70 0.74
1 20 600 -10% 600 96 0.87 0.89
Different Sample Size
1 10 300 -10% 600 34 0.55 0.56
1 10 600 -10% 600 66 0.70 0.74
1 10 900 -10% 600 89 0.83 0.82
1 10 1200 -10% 600 98 0.85 0.85
Different Mean Weight Reduction
1 10 600 -5% 600 14 0.30 0.38
1 10 600 -8% 600 42 0.56 0.61
1 10 600 -10% 600 66 0.70 0.74
1 10 600 -13% 600 92 0.84 0.84
1 10 600 -15% 600 98 0.88 0.88
1 10 600 -20% 600 100 0.93 0.93
Different Standard Deviation
1 10 600 -10% 300 100 0.93 0.93
1 10 600 -10% 600 66 0.70 0.74
1 10 600 -10% 900 28 0.45 0.51