2.2 : データ: 種類と分布

In biostatistics, data refers to the collected observations that are subject to analysis. Data can be parametric or nonparametric.

Nonparametric data doesn't follow any specific distribution. It includes categorical data, both nominal, like gender, and ordinal, such as pain scale ratings.

Parametric or quantitative data assumes a specific distribution pattern. It includes numerical data, both continuous, like weight, and discrete, such as number of tablets.

Distributions in biostatistics indicate the arrangement of data points on a graph.

Normal or Gaussian distribution is a symmetrical distribution where mean, median and mode coincide. For instance, baby birth weights typically follow a normal distribution.

Skewed distributions have data points asymmetrically distributed around the mean.

A positive skew indicates a long tail towards the right, exemplified by drug metabolite concentrations in a patient's blood.

A negative skew shows a long tail towards the left, one example of this being the cost of branded drugs.