[R] Need some help

Daniel Nordlund res90sx5 at verizon.net
Mon Oct 15 07:47:07 CEST 2007

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf
> Of azzza
> Sent: Sunday, October 14, 2007 10:21 PM
> To: r-help at r-project.org
> Subject: [R] Need some help
> Hi!
> I'm taking a course that requires some programming background, but I'm a
> complete novice in the field.
> when asked to generate a list of 20 uniform random numbers, is it alright if
> I put in >randu, and just copy-paste the first 20 numbers?? Or is there, as
> I suspect, a better way of calling out exactly 20 uniform random numbers??
See ?runif

rand_nums <- runif(20)

> I'm also unable to solve the following problem:
> We know that on average 30% of the customers who enter a store make a
> purchase. Suppose 200
> people enter the store today. Run a simulation to see how many purchases we
> will have today.
see ?sample
> number_of_purchases <- sum(sample(c(0,1), 200, prob=c(.70, .30), replace=TRUE))

Hope this is helpful,


Daniel Nordlund
Bothell, WA USA

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