Absolute, relative, cumulative frequency and statistical tables
In a survey to $20$ inhabitants of Barcelona on how many times a week they buy in small shops in the city, the obtained answers are: $$2,0,3,1,4,5,1,1,2,3,0,0,1,3,2,5,4,3,3,2$$
Construct a frequency table and calculate what percentage of the population make purchases $3$ times or less per week in small shops.
| Purchases in small shops | Absolute frequency $f_i$ | Relative frequency $n_i$ | Cumulative frequency $F_i$ | Cumulative relative frequency $N_i$ |
| $0$ | $3$ | $\dfrac{3}{20}$ | $3$ | $\dfrac{3}{20}$ |
| $1$ | $4$ | $\dfrac{4}{20}$ | $3+4=7$ | $\dfrac{7}{20}$ |
| $2$ | $4$ | $\dfrac{4}{20}$ | $3+4+4=11$ | $\dfrac{11}{20}$ |
| $3$ | $5$ | $\dfrac{5}{20}$ | $11+5=16$ | $\dfrac{16}{20}=0,8=80\%$ |
| $4$ | $2$ | $\dfrac{2}{20}$ | $16+2=18$ | $\displaystyle\frac{18}{20}$ |
| $5$ | $2$ | $\dfrac{2}{20}$ | $18+2=20$ | $\dfrac{20}{20}=1$ |
| $\sum$ | $20$ | $1$ |
| Purchases in small shops | Absolute frequency $f_i$ | Realtive frequency $n_i$ | Cumulative frequency $F_i$ | Cumulative relative frequency $N_i$ |
| $0$ | $3$ | $\dfrac{3}{20}$ | $3$ | $\dfrac{3}{20}$ |
| $1$ | $4$ | $\dfrac{4}{20}$ | $3+4=7$ | $\dfrac{7}{20}$ |
| $2$ | $4$ | $\dfrac{4}{20}$ | $3+4+4=11$ | $\dfrac{11}{20}$ |
| $3$ | $5$ | $\dfrac{5}{20}$ | $11+5=16$ | $\dfrac{16}{20}=0,8=80\%$ |
| $4$ | $2$ | $\dfrac{2}{20}$ | $16+2=18$ | $\displaystyle\frac{18}{20}$ |
| $5$ | $2$ | $\dfrac{2}{20}$ | $18+2=20$ | $\dfrac{20}{20}=1$ |
| $\sum$ | $20$ | $1$ |
$80\%$ of the survey participants make purchases $3$ times or less per week in small shops.