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The process of calculating Poisson probabilities using a TI-84 calculator involves entering the appropriate values into the calculator and using the Poisson probability function to obtain the desired result. This function can be found under the “DISTR” menu and is denoted as “poissonpdf”. By inputting the appropriate parameters, such as the mean and the desired value, the calculator will provide the probability for that specific event occurring. This method is useful for solving problems and making predictions in fields such as statistics and probability. With its user-friendly interface and efficient calculations, the TI-84 calculator is a reliable tool for computing Poisson probabilities.
Calculate Poisson Probabilities on a TI-84 Calculator
The is one of the most commonly used distributions in all of statistics. This tutorial explains how to use the following functions on a TI-84 calculator to find Poisson probabilities:
poissonpdf(mean, x) returns the probability associated with the Poisson pdf.
poissoncdf(mean, x) returns the cumulative probability associated with the Poisson cdf.
where:
- mean = mean number of “successes”
- x = specific number of “successes”
Both of these functions can be accessed on a TI-84 calculator by pressing 2nd and then pressing vars. This will take you to a DISTR screen where you can then use poissonpdf() and poissoncdf():
The following examples illustrate how to use these functions to answer different questions.
Example 1: Poisson probability of exactly x successes
Question: A hardware store sells 3 hammers per day on average. What is the probability that they will sell 5 hammers on a given day?
Answer: Use the function poissonpdf(mean, x):
poissonpdf(3, 5) = 0.1008
Example 2: Poisson probability of less than x successes
Question: A hardware store sells 3 hammers per day on average. What is the probability that they will sell less than 5 hammers on a given day?
Answer: Use the function poissoncdf(mean, x-1):
poissoncdf(3, 4) = 0.8153
Example 3: Poisson probability of at most x successes
Answer: Use the function poissoncdf(mean, x):
poissoncdf(3, 5) = 0.9161
Example 4: Poisson probability of more than x successes
Question: A hardware store sells 3 hammers per day on average. What is the probability that they will sell more than 5 hammers on a given day?
Answer: Use the function 1 – poissoncdf(mean, x):
1 – poissoncdf(3, 5) = 0.0839
Example 5: Poisson probability of at least x successes
Question: A hardware store sells 3 hammers per day on average. What is the probability that they will sell at least 5 hammers on a given day?
Answer: Use the function 1 – poissoncdf(mean, x-1):
1 – poissoncdf(3, 4) = 0.1847