Probability Flashcards
What is probability?
the ratio of having a particular outcome among all possible outcomes would converge to a certain number between zero
and one
What is the alternative view of probability?
a measure of belief about the predicted outcome of an event.
What is a discrete random variable
can take on a finite or countably infinite number of distinct values.
What is probability mass function
Function that gives the probability that a discrete random variable is exactly equal to some value
What is a continuous random variable
A continuous random variable in statistics is a variable that can take any value within a certain range or interval. Unlike discrete random variables, which can only take on specific, distinct values, continuous random variables can take on an infinite number of values within a given range.
Probability distribution function
a function that describes the likelihood of a continuous random variable taking on a particular value or falling within a particular range of values.
What is binomial distribution?
counts the total number of successes out of n trials, where X is the number of successes.
Characteristics of binomial distribution
- Each trial must be independent of the previous trial/experiment
- The probability of success must be the same for each trial
Set of assumptions required for binomial distribution
- A set of n experiments or trials are conducted
- Each trial could result in either a success or a failure
- The probability p of success is the same for all trials
- The outcomes of different trials are independent
- We are interested in the total number of successes in these n trials.
What is the binomial distribution formula?
P(x) = (n! / x!(n-x)!) * p^x*q^n-x
n = number of trials or number getting sampled
x = the number of successes desired
p = probability of success
q = 1-p
The probability of observing any sequence of n independent trials that contain x successes and n-x failures is
p^n * (1-p)^n-x
Total number of possible sequences
n! / x! * (n-x)!
When does binomial distribution attain it’s peak?
at p times n
What is poisson distribution?
a probability distribution used to model the number of events that occur in a fixed interval of time or space when the events happen independently and at a constant average rate