Janice Pogue Lecture in Biostatistics, Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada 2024-12-06 Slides| Statistical Thinking
Background Consider these four conditions: There is no reliable prior information about an effect and an uninformative prior is used in the Bayesian analysis There is only one look at the data The look was pre-planned and not data-dependent A one-sided assessment is of interest, so that one-tailed p-values and Bayesian posterior probabilities are used, where is the effect parameter of interest (e.g., difference in means, log effect ratio) and means “conditional on” or “given”. One-Sid...| Statistical Thinking
Background A binary endpoint in a clinical trial is a minimum-information endpoint that yields the lowest power for treatment comparisons. A time-to-event outcome, when only a minority of subjects suffer the event, has little power gain over a pure binary endpoint, since its power comes from the number of events (number of uncensored observations). The highest power endpoint would be from a continuous variable that is measured precisely and reflects the clinical outcome situation. An ordinal ...| Statistical Thinking
Background The log-rank test is a Mantel-Haenszel “observed - expected frequency” type of test that was derived in a slightly ad hoc way by Nathan Mantel in 1966 and named the logrank test by R Peto and J Peto in 1972. It was later formally derived as the rank test having optimal local power for a shift in the type I extreme value (Gumbel) distribution. This horizontal shift is equivalent to a vertical shift in survival distributions after log-log transforming them. This is identical to s...| Statistical Thinking
A Definition All statistical procedures have assumptions. Even the most simple response variable (Y) where the possible values are 0 and 1, when analyzed using the proportion that Y=1, assumes that Y is truly binary, every observation has the same probability that Y=1, and that observations are independent. Non-categorical Y have more assumptions. Even simple descriptive statistics have assumptions as described below. But what does it mean that an assumption is required for using a statistica...| Statistical Thinking