Tamil Nadu Open University (TNOU) 2007 B.Sc Statistics maths - Question Paper

Permutation and combination
a) Fundamental principal of addition: if 1 thing can be done m number of ways and other thing can be done in n number of ways independent of other. Then either of them can be done in (m+n) ways
b) Fundamental principal of multiplication: if 1 thing can be done m number of ways and other thing can be done in n number of ways independent of other. Then either of them can be done in (m*n) ways
c) Permutation : permutation of n objects taken r at a time is the arrangement in a straight line of r objects taken at a time denoted by N!/(N-R)!
d) The number of permutation of n objects taken all at a time = n!
e) The number of permutations of n objects taken all at a time when p of them are like, q are like = n!/p!q!
f) Combination is the selection of r objects in n objects. Denoted as N!/(n-r)!r!
g) Number of permutations of n objects taken all at a time in circle (n-1)!
h) When the repetition of allowed then permutation nr

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