This paper offers class mark estimators for the intervals of a grouped frequency distribution, derived by parabolic interpolation between any given interval and its adjacent intervals. The objective ...

Tallying is a way of recording data that counts in groups of five. The data is tallied as it is counted, with a mark for each piece of data, and then the frequency is recorded at the end. Frequency ...

There are 30 students, so we are looking for the group which contains the \((30 + 1) \div 2 = 15\frac{1}{2}th\) value, which lies halfway betwen the 15th and the 16th value. The cumulative frequency ...