From the following data, cumulative frequency for the class $\displaystyle 20-30$ isClass | $\displaystyle 0-10$ | $\displaystyle 10-20$ | $\displaystyle 20-30$ | $\displaystyle 30-40$ | $\displaystyle 40-50$---|---|---|---|---|---Freq | $\displaystyle 4$ | $\displaystyle 6$ | $\displaystyle 20$ | $\displaystyle 8$ | $\displaystyle 3$

On ______ the frequency, starting from a rather low value, gradually reaches the maximum value, somewhere near the central part and then gradually decreases to reach its lowest value at the other extremity.

Divided bar chart is considered for

Data are said to be ______ if the investigator himself is responsible for the collection of the data.

A suitable graph for representing the portioning of total into sub parts in statistics is:

The average of salaries in a factory is $\displaystyle 47,000$. The statement that the average salary $\displaystyle 47,000$ is

Statistics cannot deal with ______ data.