1 DATA AND SAMPLING

• A millions of data emerge in businesses every day and statistics helps us to organize, summarize, analyze, and interpret these data

• If we would like to benefit from statistics we should analyze our data properly

The appropriateness of the data analysis depends on the level of measurement of the data, e.g.
averaging the weights of students seems reasonable, but averaging hair color makes no sense

• Organizing and summarizing data is called descriptive statistics, while inferential statistics uses probability to determine how confident we can be that our conclusions are correct

Inference is the process of making decisions or conclusions about a population based on
random sample

• If the data are nominal or ordinal, nonparametric statistics must be used, while parametric statistics requires interval or ratio data