Biostatistics (class 1 to class 4)

Random variable

takes a particular outcome by chance. Its behavior follows a probability distribution.

Expectation

the sum of the expected values

Variance

the sum of squared deviations divided by the number of observations minus 1; how far data spreads out from the mean

Probability distribution

a list of all the possible outcomes of a random variable along with their corresponding probability values.

Sensitivity

the probability of a positive test result when disease is present

Specificity

the probability of a negative test result when disease is absent

Positive predictive value (PPV)

the probability that disease is present when a test result is positive

Negative predictive value

the probability that disease is absent when test results are negative