/guava/android/guava/src/com/google/common/math/Stats.java
checkState( count != 0) ;checkState( count > 1) ;
checkState ( count > 1 ) ;
return ensureNonNegative(sumOfSquaresOfDeltas) / count(); } public double populationStandardDeviation() { return Math.sqrt(populationVariance()); } public double sampleVariance() { <extra_id_0> if (isNaN(sumOfSquaresOfDeltas)) { return NaN; } return ensureNonNegative(sumOfSquaresOfDeltas) / (count - 1); } public double sampleStandardDeviation() {