An auditor reviewing the invoices of a small company finds that ...

[Mr. Wonderful]

An auditor reviewing the invoices of a small company finds that there are errors in 1.5 of them.
 
  If the auditor looks at 500 invoices, what is the probability that he finds more than 3 invoices with errors? Use the Poisson approximation to the binomial distribution.

Question 2

The conditional probabilities P(A  B ) and P(B  A ) are always equal.
 
  Indicate whether the statement is true or false

[SAUXC]

Answer to Question 1

 = nP = 7.5, then P(X > 3 ) = 1 - P(X  3 ) = 1 - (0.0006 + 0.0041 + 0.0156 + 0.0389 ) = 0.9408

Answer to Question 2

FALSE