[227126] Compare 2-gram histograms of proper english lines vs garbage text

LS englishLines = tlft(gazelle_text(226918));
LS garbageLines = tlft(gazelle_text(226969));
int n = 2;

// reference histogram (10,000 english sentences)
Map<S, Double> full = multiSetToHistogramWithSum1(ngramsHistogram_multipleStrings(n, englishLines));

embedded double chi(S line) {
  ret chiSquared_histogramsWithSum1(multiSetToHistogramWithSum1(ngramsHistogram(n, line)), full);
}

L<Double> l1 = safeMap(s -> chi(s), takeFirst(100, englishLines));
L<Double> l2 = safeMap(s -> chi(s), garbageLines);

ret findBestThreshold(l1, l2);