PROBLEM 4. Middle mechanism of the group

Doors No. of No. of
Settings open doors open right door
1..................2.3.4......................3..................3
2..................5.6.7.8.9..................5..................7
3..................1.2.3.4.5.6.7..............7..................4
4..................7.8.9......................3..................8
5..................4.5.6.7.8..................5..................6
6..................1.2.3.4.5.6.7.8.9..........9..................5
7..................1.2.3......................3..................2
8..................2.3.4.5.6..................5..................4
9..................3.4.5.6.7.8.9..............7..................6
10..................6.7.8......................3..................7
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Total 50



It was found desirable after a problem had been solved to present a new
and radically different series of settings in order to determine to what
extent the subject had learned to choose the correct door by memorizing
each particular setting. These supplementary observations may be known
as control experiments, and the settings as supplementary settings. In
case of these, as for the original settings, the essential facts are
presented in tabular arrangement.