  This is the write-up of a set of lectures given at the Asia Europe Pacific
School of High Energy Physics in Quy Nhon, Vietnam in September 2018, to an
audience of PhD students in all branches of particle physics They cover the
different meanings of 'probability', particularly frequentist and Bayesian, the
binomial, Poisson and Gaussian distributions, hypothesis testing, estimation,
errors (including asymmetric and systematic errors) and goodness of fit.
Several different methods used in setting upper limits are explained, followed
by a discussion on why 5 sigma are conventionally required for a 'discovery'.
