Figure 4. A snapshot, in time, of two complex numbers whose exponents, and thus their phase angles, change with time. The notion of negative frequency is often troubling to engineers who've spent so ...

Quartiles are the values that divide a data set into quarters: Put the values in order Divide the list into four equal parts The Quartiles are at the divisions The interquartile range shows the range ...

Frequency tables and diagrams record the number of times something happens. Recording the frequency of disease is important. Frequency tables and diagrams allow scientists to look at correlations.