What is PMF - discreet distributions
what random variables does it use
Probability mass function
discrete random vairables
what does PMF give - DD
what does mass mean
probabilty that X takes an exact value
each DRV carries a mass (chunk) of probability
What is PDF - DD
what random variables does it use
Proabbilotiy density function
Continuos random variable
probability that x takes a value at or below a certain value
what does density mean in PDF - DD
Proabiltiy spead across a range, no single point has mass
meause hwo dense the probability is in an interval
What is Bernoulli distribution ?
how is the probabilty written for this
One experiment with two possible outcomes
Success = p
fail = 1-p
what are the properties of binomial distribution
Experiment has n identical trials
Two possible outcomes (suc/fail)
probability of success defined by p
trials are independent
what does PDF show - DD
probability that x takes a value at or below a certain value
when do you use bernoulli
what would the question look like
1 experminet
2 outcomes
single event
does a single person pay?
when do you use binomial
what kind of question would it be
n number of experiments
0-n successes
count of successes
how many clients pay
How does CDF work for continuos distributions
expresses the probabiloty that X doesnt exceed the value of x
How do you find the proabbilty that X falls in a range using CDF
difference between cummaltive proababilty of upper end and lower end of range
Whats uniform distribution
When the probabilities of outcomes in the sample space are the same
probability is “uniformaly distributed”
where is the mean, median and mode on a normal distribution?
how does the standard deviation affect it?
in the middle
dteermines the width of the curve - larger results resukts in wider, flatter curves
how do the percenatge of values change wsithing incrwasing numbers of standard devaitions on normal distribution
68% - 1 SD
95% - 2 SD
99% - 3 SD
whats the Z-score formula
observations minus mean / standard deviaton
What does a Z-score tell you
how many standard deviations the data point is away from the mean
