{'fraction_non_alphanumeric': 0.024943310657596373, 'fraction_numerical': 0.026077097505668934, 'mean_word_length': 4.886666666666667, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Recognising Randomness David Green

THE concept of randomness is something we all think we understand, but to provide an acceptable definition is by no means straightforward. To us it is more of an intuition and we all know that intuition can let us down! In a recent interesting article Chatterjee (1996) discussed the difficulties encountered when considering randomness, which has its echoes in a project undertaken by the author some time ago (see Green, 1991 for a fuller report). The project involved 1600 English primary school pupils, aged 7 to 11, and 300 secondary school pupils aged 13-14, each of whom was given a half-hour paper-based test on concepts of randomness. One test item involved selection from a uniform distribution. A class demonstration was first undertaken with pupils selecting, with replacement, numbered counters using the scenario depicted in Fig. 1.