R help - Apr 2010 - Struggling with two questions : Newbie student .

Hi ,

I am struggling with these two question . Any help would be appreciated ,Im
looking at doing them on r ?

1. Tests for indications of asbestos in the lungs of employees at an
insulation manufacturer resulted in four persons with positive indications
of asbestos being sent to a medical center for further testing . if 45% of
the employees have positive indications of asbestos in their lungs , find
the probability that twelve employees must be tested in order to find the
four positives to send for further testing ?

2. In a small scale trial five seeds are treated with fungicide and five
seeds are untreated with fungicide. Seeds were then planted and the number
was counted . If four plants actually sprouted what is the probability that

a) all four plants emerged form the treated seeds.
b)Three of few emerged from the treated seeds

Regards

Malcolm

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malcolm Crouch <malcolm.croucher <at> gmail.com> writes:
> 1. Tests for indications of asbestos in the lungs of employees at an
> insulation manufacturer resulted in four persons with positive indications
> of asbestos being sent to a medical center for further testing . if 45% of
> the employees have positive indications of asbestos in their lungs , find
> the probability that twelve employees must be tested in order to find the
> four positives to send for further testing ?
> 
> 2. In a small scale trial five seeds are treated with fungicide and five
> seeds are untreated with fungicide. Seeds were then planted and the number
> was counted . If four plants actually sprouted what is the probability that
> 
> a) all four plants emerged form the treated seeds.
> b)Three of few emerged from the treated seeds
  This looks like homework, and there is a (formal? informal?) "no
homework help" policy on this list (because there is no way for
other list readers to know whether or not getting help in this way
is within the scope of your allowed resources).  

  However, I will hint that all the tools you need to do these
problems are in fact available in R.  See
http://rwiki.sciviews.org/doku.php?id=tips:stats-distri:0verview
for information on distributions and what you can do with them
(additional hint: all of this is possible in base R, you won't
have to install any additional packages).