Distribución de Poisson en Excel

How to Calculate Probability Values in Excel

Introduction to the Probability Function

• The tutorial focuses on obtaining probability values for a random variable x , which represents the number of times a cat eats from its bowl daily.

• The example uses a Poisson distribution, considering values of x ranging from 0 to 15, including scenarios where the cat does not eat at all.

Setting Up Parameters

• The parameter lambda , representing the expected value (mean) of the distribution, is set to 10, indicating that on average, the cat eats 10 times per day.

• To calculate probabilities in Excel, users will input a function that requires selecting specific cells for both x and lambda .

Using Excel Functions

• When entering the formula in Excel, it’s crucial to fix the cell reference for lambda by adding a dollar sign before the row number (e.g., $3). This ensures that as formulas are dragged down for other values of x , this reference remains constant.

• Users can choose between cumulative distribution functions or just probability functions by setting an argument in their formula: using 1 (true) for cumulative or 0 (false) for just probability.

Calculating and Visualizing Probabilities

• After entering the formula with appropriate parameters, users can compute probabilities. For instance, when x = 0, the calculated probability is approximately 4.54 × 10^-5.