Measures of Dispersion

Also called “measure of variability or spread” range – difference between the highest and lowest values + often both extremes are reported with it interquartile range – alternative measure, less influenced by extreme values = range of the...

Measures of central tendency

the mean – arithmetic mean or average = sum(x1..xn) / n appropriate for interval and ratio data in physical meaning represents point of balance the median – middle value of a data set when values are in ASC or DESC order mathematically defined as (n+1)/2th...

Probability – basics

Probability generaly refers to an event whose outcome is unknown – if we would know the outcome we do not need to check probability. Probability tells us how often some outcome is likely to occur when an experiment is repeated. Conditional probability –...

Types of data

nominal data – numbers are use as substitute for names or labels and do not have meaning as number – typicaly “enumerated type” in database, in special case “binary data” ordinal data – data has some meaningful order, higher...