How to calculate needed sample size
9 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
I have a probability of an infection happening as 0.0001
I need to find exactly how many patients would have to come in to have the chance of an infection being 50%
I did it on my calculator and its somewhere between 6,800-7,000 but I need the matlab code to determine the exact number.
0 commentaires
Réponses (1)
Walter Roberson
le 25 Sep 2021
Remember,
Probability of an event occurring at least once in n tries is 1 minus the probability that the opposite event happens every time for n tries. Probability that the opposite event happens every time is (1-p)^n, so overall probability is 1 - (1-p)^n
For 50% chance you want the result to equal 1/2, 1 - (1-p)^n == 1/2 . So (1-p)^n == 1 - 1/2 .
Now take the log of both sides: n * ln(1-p) == ln(1/2) . Divide: n = ln(1/2) / ln(1-p) .
Now implement in MATLAB.
0 commentaires
Voir également
Catégories
En savoir plus sur MATLAB Coder dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!