Probability Fundamentals Vocabulary

a measure of the likelihood that an event will occur

“The probability of rolling a six is 1/6.”

randomly determined; having a random probability distribution

“Stock prices follow a stochastic process.”

a variable whose value is determined by chance

“The number of heads in 10 coin flips is a random variable.”

the long-run average value of a random variable

“The expected value of a fair die roll is 3.5.”

a measure of how spread out a distribution is

“High variance indicates data points are far from the mean.”

the square root of variance; a measure of dispersion

“Most data falls within two standard deviations of the mean.”

a function showing all possible values and their probabilities

“Test scores often follow a normal distribution.”

events where one does not affect the probability of another

“Successive coin flips are independent events.”

the probability of an event given that another has occurred

“The conditional probability of rain given clouds is higher than without.”

a formula for updating probabilities based on new evidence

“Bayes' theorem helps doctors interpret diagnostic test results.”