(from ZX Computing Aug/Sep'84)

Telepathy
---------

Keep your mind clean, you never know who is
tuning in! Chris H. Sinclair of North Humberside helps
to test your ability.
---------------------

Parapsychology is now a growing area of 'respectable' research.
Investigations in this field include research into Telepathy
and Precognition and to aid such investigations, Dr J.B. Rhine
designed a pack of cards known as Zener cards.

  A pack consists of 25 cards, each marked with either a cross,
a square, wavy lines, a circle, or a star. In telepathy and
precognition experiments a card is randomly chosen by a person
and the subject under test must guess which card has been
chosen. However, it was found that testers tended to pick the
cards in a certain sequence. Subjects can subconsciously
pick-up these sequences, leading to misleading results. To
overcome this, the card sequence is chosen by computer.

  This program simulates such an experiment on your Spectrum,
drawing the five Zener cards and asking for the subject for
100 guesses. The Spectrum then prints the percentage of
correct guesses made.


The Program
-----------

User defined graphics are used in printing the 'star' and the
'wavy lines' cards. The data for the graphics is held in lines
50000-5240 and lines 50-80 define these graphics. The
subroutine starting at line 4000 clears the screen and draws for
five Zener cards. Line 190 defines the variables used in the
program. Lines 310-410 form the main guess loop. Lines 320-330
defines a random number between 1 and 5. And lines 340-370 get
a keypress between 1 and 5. If the guess is the same as
the random number generated then 'correct' is increased by
one. Line 390 produces short delay (Approx  of a second)
before looping to 310 again. This loop is performed 100
times. Lines 510-520 calculates the percentage of
correct guesses whilst line 550-590 prints the percentage
in large figures, lines 560-570 print the 'tens' part whilst lines
580-590 print the 'units'.


Variables
---------

CORRECT            - No. of correct guesses made.
NO                 - Random no. generated.
GUESS              - No. guessed by subject.
TRIES              - No. of times guess loop is executed.
GO                 - Controls position on screen of large no. to
                     be printed.
a,b,c,r,d,y,       - For general use.
G$                 - Guess input from keyboard.
Y$                 - 'Y' or 'N' input.


Interpreting
Results
-------

It should be realised that what is to follow is an over simplification
of  what is and is not 'significant'. In 5 guesses we
may expect to guess 1 correctly by pure chance. Therefore, in
100 guesses we may expect to obtain a 20% score by pure
chance. Any score above 20% may, if repeatable, indicate
paranormal abilities.

  The snag is that statistically speaking, 100 guesses is quite a
small sample and so the definition of significance must be
altered to account for this. In general it should thus be accepted
that scores above around 25% may indicate paranormal abilities.

  Finally, those interested in current work in this field could
do a lot worse than consult Kit Pedler's book 'Mind Over Matter'
published by Thames/Methuen. This book provides an
ordinary persons guide to the subject in simple, highly
readable language. Above all, it presents a sober, non-
sensationalist outlook. A definite antidote for those suffering
with an overdose of the Von-Daniken's.
