Question

Internet sites often vanish or move so that references to them cannot be followed. In fact, 13% of Internet sites referenced in major scientific journals are lost within two years after publication.

If a paper contains six Internet references, what is the probability that all six are still good two years later? Round your answer to three decimal places.

What specific assumption must be made in order to calculate the probability?

A) One does not need to make any assumptions; this is just a straightforward calculation.

B) The occurrence of the site references in the paper are disjoint events,

C) The paper containing the references must be obtained by random sampling.

D) The occurrence of the site references in the paper are independent events.

?(all six are still good) =

Answer 1

Assumption made: The occurrence of the site references in the paper are independent events.

Option D is correct.

P(All six still good) = (1 - 0.13)⁶ = 0.87⁶ = 0.4336