Statistics ch. 4-6
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Statistics ch. 4-6
what is random variable, how many types and identify them?
"x" represents a numerical value associated with each outcome of a probability experiment
"x" is totally by CHANCE
Two types:continuous and discrete
What is discrete random variable?
a variable that has a finite or COUNTABLE number of possible outcomes that can be listed
what is continuous random variable?
a random variable that has an UNCOUNTABLE number of possible outcomes, represented by an interval on the NUMBER LINE
What is the difference between discrete random variables and continuos random variables?
discrete random variables represent COUNTED data
continuous random variables represent MEASURED data
INIGHT: VALUES OF VARIABLES ROUNDING
age, height, and weight are usually rounded to the nearest year, inch, or pound
THESE ARE MEASURED DATA AND ARE CONTINUOUS RANDOM VARIABLES
what is a binomial experiment?
probability experiments that are reduced to two outcomes: success and failure
what are the conditions of binomial experiment?
1. repeated independent trials
2. two outcomes of trial
: success or failure
3. the probability f success P(S) is the same for each trial
4. the random variable "x" counts the number of successful trials
What is geometric distribution?
a discrete probability distribution of a random variable "x"
what are the characteristics of geometric distribution?
1. trial is repeated until SUCCESS occurs
2. repeated trials are independent of ear other
3. the probability of success "p" is constant for each trial
4. the "x" represents the number of the trials in which the first success occurs.
5. the parameter of a geometric distribution is "p"
What is Poisson distribution?
a discrete probability distribution of a random variable "x''
what are the characteristics of Poisson Distribution?
1. the experiment consists of counting the number of times "x" an event occurs over a specified interval of time, area, or volume
2. the probability of the event occurring is the same for each interval
3. the number f occurrences in one interval is independent of the number of occurrences in other intervals
4. the parameter of a poisson distribution is "mu"