Dr. Ir. Djunaedi Kosasih, MSc.

## Opening Issues

## Reference

Basic Statical Methods for Engineers and Scientists (2^{nd} Edition), JB Kennedy an AM Neville, Harper International Edition, 1976

## Population vs Sampel

**Population**is the set of elements of interest for a given problem**Random Sample**is a subset of the population such that each member of the population is equally likely to be selected

*If we are to judge the population (whole) from sample (part), the sample must be as representative of the population as possible*

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## Mathematics vs Statistics

**Mathematics**produces exact solutions, i.e. either a variable has a particular value (Prob = 1) or it does not have that particular value (Prob = 0)**Statistics**deals with a variable that can take on many possible values. This probability can have any value between 0 and 1

*By means of statistic we attempt to define and control the extent of the uncertainty that is due to the inevitable variability of the data*