Biostatistics with R/Some Basic Probability Concepts

Formular with R Formular Number Name Formular Formular with R 3.2.1 Classical probability Example 3.2.2 Relative frequency probability Example 3.3.1–3.3.3 Properties of probability Example 3.4.1 Multiplication rule Example 3.4.2 Conditional probability Example 3.4.3 Addition rule Example 3.4.4 Independent events Example 3.4.5 Complementary events Example 3.4.6 Marginal probability Example Sensitivity of a screening test Example Specificity of a screening test Example 3.5.1 Predictive value positive of a screening test Example 3.5.2 Predictive value negative of a screening test Example Symbol Key = disease = Event = the number of times an event E_i occurs = sample size or the total number of times a process occurs =Population size or the total number of mutually exclusive and equally likely events = a complementary event; the probability of an event A, not occurring =probability of some event E_i occurring =an “intersection” or “and” statement; the probability of an event A and an event B occurring =an “union” or “or” statement; the probability of an event A or an event B or both occurring =a conditional statement; the probability of an event A occurring given that an event B has already occurred =test results Example