Moments
Skewness and kurtosis are two of the first four moments of a normal distribution. Both can be used to test the assumption of normality of a data distribution, although they are less widely used than other contrast pr graphical methods.
Science without sense...double nonsense
Evidence Based Medicine pills
Science without sense...double nonsense
Evidence Based Medicine pills
Category Statistics
Counting bugs
The geometric mean is used when the values of the data distribution change multiplicatively, and not additively. This makes it ideal for averaging geometric progression data, such as ratios, compound interest in economics, or bacterial growths in microbiology.
A picture is worth a thousand words
There are three possible strategies o verify that a variable follows a normal distribution: methods based on hypothesis testing, those based on graphical representations and the so-called analytical methods.
A tricky riddle
The harmonic mean is the reciprocal of the arithmetic mean. It is calculated as the total number of observations divided by the sum of the reciprocals. It is used in situations in which it is necessary to average paths of equal length with different times, as well as to average multiples or quotients.
A measure with a pedegree
The sample size required to estimate a population mean depends on the desired level of confidence and precision, in addition on the variable’s variance in the population.