The monthly income of a group of 320 employee in a company is given below
| Monthly income (thousands) | No.of employee |
| 6-7 | 20 |
| 7-8 | 45 |
| 8-9 | 65 |
| 9-10 | 95 |
| 10-11 | 60 |
| 11-12 | 30 |
| 12-13 | 5 |
Draw an ogive of the distribution on a graph paper taking 2 cm = rS 1000 on one axis and 2 cm = 50 employee on the other axis. From the graph detemine:
(1) the median wage.
(2) number of employee whose income is below Rs 8500
(3) If salary of a senior employee is above Rs11,500 find the number of senior employee in the company.
(4) the upper quartile.
Solution
| Monthly income (thousands) | No.of employee (f) | Cumulative frequency |
| 6-7 | 20 | 20 |
| 7-8 | 45 | 65 |
| 8-9 | 65 | 130 |
| 9-10 | 95 | 225 |
| 10-11 | 60 | 285 |
| 11-12 | 30 | 315 |
| 12-13 | 5 | 320 |
| Total | 320 |
Number of employees = 320
Median`=320/2=160^("th")` term
Though marks 160. draw a parallel line to x-axis which the curve at A draw a perpendicular to x-axis meeting it at B the value of point B is the median = Rs 9.3 thousands
The number of employees whit income below Rs 8500 = 95 (approx from the graph )
Number of employee with income below Rs 115 - 305 (approx from the graph )
Therefore number of employee with income (senior employees) = 320 - 305 = 15
Upper quartile = `Q_3=320xx3/4=240^"th"` term = 10.3 thousands = Rs,10,300
