Questions 16-19. For each of the situations described below, give the name of the probability distribution of the random variable.

Q16) In a factory, accidents occur at random according to a Poisson distribution with an average of two accidents per month. Let T be the time elapsed between two successive accidents. The probability distribution of T is : - The normal distribution - The exponential law - The geometric law - Poisson's law - Impossible to determine

Q17) A vaccine manufactured by the company Rolo is not effective in 0.001% of cases. Let X be the number of people who will receive the vaccine before a non-effective vaccine is administered to a person. The probability distribution of X is : - The binomial distribution - The Poisson distribution - The geometric distribution - The negative binomial distribution - Impossible to determine

Q18) An official of the Federal Revenue Agency learns that out of 25 tax returns received, 9 contain illegitimate deductions. He decides to take 6 reports at random from this batch and to check them. Let X be the number of tax returns containing illegitimate deductions in this batch of 6. The probability distribution of X is : - The binomial distribution - The hypergeometric law - The geometric law - The negative binomial law - Impossible to determine Q19) The company UNIK estimates that 80% of the metal tubes it manufactures conform. Let X be the number of metal tubes to be manufactured in order to obtain 3 that comply. The probability distribution of X is : - The binomial distribution - The hypergeometric law - The geometric law - The negative binomial law - Impossible to determine