Statistical Inference Vocabulary

a procedure for deciding between competing claims about a population

“Hypothesis testing revealed the drug was more effective than placebo.”

the default assumption that there is no effect or difference

“We reject the null hypothesis if p < 0.05.”

the probability of observing results as extreme as the data, assuming the null hypothesis

“A p-value of 0.03 suggests the result is unlikely due to chance.”

a range of values likely to contain the true population parameter

“The 95% confidence interval for the mean is 45 to 55.”

the quality of being statistically unlikely to occur by chance

“The difference was statistically significant at the 0.01 level.”

the probability of correctly rejecting a false null hypothesis

“We need a larger sample to achieve adequate statistical power.”

incorrectly rejecting a true null hypothesis (false positive)

“Convicting an innocent person is analogous to a type I error.”

failing to reject a false null hypothesis (false negative)

“Missing a real disease is a type II error in medical testing.”

a subset of a population selected for analysis

“A random sample of 1000 voters was surveyed.”

systematic error that skews results in a particular direction

“Selection bias can invalidate survey results.”