Statistics and Probability Answers

A discrete random variable has probability mass function, P(X = n) =

Emmanuel is given a multiple choice exam with ten questions and each question with 5 possible answers.He decided to guess randomly for each question. What is the probability that he will get at least 6 questions correct

Suppose that a ball is drawn at random from a box containing three white & three black balls . After a ball is drawn , it is then replaced & another drawn. What is the probability that of the first four balls drawn, exactly two are white?

A random variable X has Poisson distribution with mean equal to 0.4. What is the probability that the random variable is greater than zero?.

Emmanuel is given a multiple- choice exam with 10 questions & each question with 5 possible answers .He decided to guess randomly for each question.What is the probability that he will get at least six questions correct?

Suppose that a busy traffic junction ,the probability p of an individual car having an accident is 0.0001. What is the probability of two or more cars being involved in an accident within this period?

The mean number of errors due to a bug occurring in a minute is 0.0001. What is the probability that no error will occur in 20 minutes?

The mean number of errors due to a bug occurring in a minute is 0.0001. What is the probability that no error will occur in 20 minutes?

A discrete random variable, X has probability mass function, P(X = n)=(1/2)n . Let Y= 1, if x is even and Y=-1, if x is odd. Find the expected value of Y, (E(Y)), to 2 decimal places.

Ahospital receives 30% of its COVID-19 vaccine shipments from Ghana Health Service and the remainder of its shipments from neighbouring West African countries. Each shipment contains a very large number of vaccine vials. For GHS’s shipments, 8% of the vials are ineffective and for the neighbouring countries, 3% of the vials are ineffective. The hospital tests 30 randomly selected vials from a shipment and finds that one is ineffective. What is the probability that the shipment came from neighbouring West African countries?