Q. Marks secured by 42 students in Economics are:
| Marks | 15 | 20 | 22 | 23 | 27 | 35 | 18 |
| Number of Students | 8 | 4 | 7 | 3 | 8 | 7 | 5 |
Q. Average age of the people of a country is shown in the following table:
| Age (years) | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 |
| People('000) | 30 | 32 | 15 | 12 | 9 |
Q. Calculate the arithmetic mean of the following frequency distribution by Direct Method:
| Class Interval | 10-20 | 20-40 | 40-70 | 70-120 | 120-200 |
| Frequency | 4 | 10 | 26 | 8 | 2 |
