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Finding Poisson Probabilities-Excel quiz

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  • What is the purpose of the =POISSON.DIST function in Excel?
    It is used to calculate Poisson probabilities for a given number of occurrences and mean rate.
  • What are the three arguments required by the =POISSON.DIST function?
    The three arguments are x (number of occurrences), mean (average rate, lambda), and cumulative (true or false).
  • What does setting the cumulative argument to FALSE in =POISSON.DIST do?
    It finds the probability that x is exactly equal to a specific value.
  • What does setting the cumulative argument to TRUE in =POISSON.DIST do?
    It calculates the probability that x is less than or equal to a specific value.
  • How do you find the probability that x is greater than a value using =POISSON.DIST?
    You use the complement rule: 1 minus the cumulative probability for x less than or equal to that value.
  • In the example, what is the mean rate (lambda) for the online retailer problem?
    The mean rate (lambda) is 15 orders per hour.
  • How would you write the Excel formula to find the probability of exactly 21 orders?
    You would use =POISSON.DIST(21, 15, FALSE).
  • How would you write the Excel formula to find the probability of no more than 21 orders?
    You would use =POISSON.DIST(21, 15, TRUE).
  • If you want to find the probability of more than 21 orders, which Excel operation would you use?
    You would use 1 minus the cumulative probability: 1 - =POISSON.DIST(21, 15, TRUE).
  • Why is the order of arguments important in =POISSON.DIST?
    Because Excel expects the arguments in a specific order: x, mean, cumulative.
  • What does the complement rule state in probability?
    It states that the probability of an event is 1 minus the probability of its complement (opposite event).
  • What is the approximate probability of exactly 21 orders in the example?
    It is approximately 0.03, or about a 3% chance.
  • What is the approximate probability of no more than 21 orders in the example?
    It is approximately 0.95, or about a 95% chance.
  • What is the approximate probability of more than 21 orders in the example?
    It is approximately 0.05, or about a 5% chance.
  • Why do the probabilities for x ≤ 21 and x > 21 add up to 1?
    Because they are complementary events, and the sum of their probabilities must equal 1.