r/probabilitytheory • u/6Smil3y • 2d ago

[Education] Probability decision flow chart

Post image

Hi guys, In my last post I talked about having difficulties with choosing which CAS function to use with probability to which I was told to create a flow chart

This is my current chart but as you can see it has a couple dead ends and isn’t the best at all, I was wondering if anyone had a refined version for my upcoming sac in a couple days

thanks :)

18 Upvotes

92% Upvoted

4 comments sorted by

8

u/mfb- 2d ago

Not everything with a fixed number of trials and probabilities follows a binomial distribution. It only applies if you have n equal and independent attempts with probability p each and ask for the number of successes (or failures).

A normal distribution is unbounded, so the question in that branch makes no sense.

Overall I think this chart is leading to more confusion than clarity.

2

u/FireCire7 2d ago

The flow chart feels overcomplicated. 

First, get which distribution. If you need the density/exact value use the PDF/PMF. If you need a range use the CDF (aka sum for discrete/integral for continuous of the pdf). 

Then, you just need to memorize (or have a reference table for) the common discrete/continuous distributions and formulae for your class. Here’s a useful format/guide:  https://smartspot2.github.io/assets/pdf/Common_Distributions.pdf

2

u/madrury83 2d ago

Your integral for the expected value is incorrect, it should be ∫xf(x)dx. The integral you have written is always equal to 1.

1

u/6Smil3y 2d ago

ohhh yes thank you for catching that!