MS 150 Statistics Fall 2001 Quiz 05
Fortytwo students were asked whether, when they are sick, they prefer to be left alone
to have some one care for them. The results are tabulated below. Note that 21 male
students indicated they prefer to be left alone, ten male students indicated they prefer
to be cared for, nine female students said they prefer to be left alone, and ten female
students prefer to be cared for.

Left alone (L) 
Cared for (C) 

Male (M) 
21 
10 
_____ 
Female (F) 
9 
10 
_____ 

_____ 
_____ 
_____ 
 Find the probability that a student in the fortytwo wants to be left alone:
P(L) = _____
 Find the complement of the above: P(Not L) = _____
 Find the probability that a student in the fortytwo wants is female:
P(F) = _____
 Find the probability that a student in the fortytwo wants is male AND wants to be left
alone :
P(M and L) = _____
 Find the probability that a student in the fortytwo wants is female AND wants to be
left alone :
P(F and L) = _____
 According to the data above, do men or women more frequently want to be left alone when
sick?
 Find the probability that a student in the fortytwo wants is female OR wants to be left
alone:
P(F or L) = _____
 Find the probability that a student in the fortytwo is female given that the student
wants to be cared for:
P(F, given C) = _____
 Find the probability that a student in the fortytwo wants to be left alone given that
the student is female:
P(L, given F) = _____
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