Statistics Year 1 Unit 6 Flashcards
Define random variable
A variable whose value depends on the outcome of a random event
Define sample space
The range of values that a random variable can take
What makes a variable random?
If the outcome is not known until the experiment is carried out
What does a probability distribution do?
Fully describes the probability of any outcome in the sample space
What is a discrete uniform distribution?
When all of the possibilities are the same
sum of P(X-x) =
1
Binomial distribution
B(n, p)
Binomial distribution formula
(n choose r)(p^r)((1-p)^(n-r))
What symbol is the index
n
What symbol is the parameter
p
When can you model x with a binomial distribution?
.When there are a fixed number of trials, n
.there are two possible outcomes
.There is a fixed probability of success, p
.The trials are in independant of each other
What does a cumulative probability function for a random variable x do?
Tell you the sum of all the individual probabilities up to and including the given value of x in the calculation for p(X<=x)
How do you find the cumulative probability function?
Either through the given table or function on the calculator
This is the phrase, what does it mean and what is the calculation used?
greater than 5
x>5
1-p(x<=5)
This is the phrase, what does it mean and what is the calculation used?
no more than 3
x<=3
p(x<=3)
