The following data on the number of girls (to the nearest ten) per thousand boys in different sections of Indian society is given below.
| Section | Number of girls per thousand boys |
|---|---|
| Scheduled Caste (SC) | 940 |
| Scheduled Tribe (ST) | 970 |
| Non SC/ST | 920 |
| Backward districts | 950 |
| Non-backward districts | 920 |
| Rural | 930 |
| Urban | 910 |
(i) Represent the information above by a bar graph.
(ii) In the classroom discuss what conclusions can be arrived at from the graph.
| Section | Number of girls per thousand boys |
|---|---|
| Scheduled Caste (SC) | 940 |
| Scheduled Tribe (ST) | 970 |
| Non SC/ST | 920 |
| Backward districts (BD) | 950 |
| Non-backward districts (NBD) | 920 |
| Rural | 930 |
| Urban | 910 |
Taking different sections of the society on the x-axis and number of girls per thousand boys on the y-axis, we draw a bar graph to represent the above data.
(i) Steps of construction :
Plot the sections on x-axis. Since, the scale on x-axis starts at 900, a break (kink) is shown near the origin on y-axis to indicate that the graph is drawn to scale beginning at 900.
Plot number of girls per thousand boys at y-axis by taking 1 unit = 10 girls.
To represent our first Head, i.e., (SC), we draw a rectangular bar with width 1 unit and height 940 units.
Similarly, other Heads are represented leaving a gap of 1 unit in between two consecutive bars.
(ii) From graph,
We can observe that :
(a) The number of girls per thousand boys under Non SC/ST and non-backward districts are same as 920.
(b) Number of girls under section Scheduled Tribe (ST) per thousand boys is maximum i.e., 970.
(c) Number of girls under section Urban per thousand boys is minimum i.e., 910.
Statistics — Interactive Study Guide
Histogram vs Bar Graph
| Feature | Bar Graph | Histogram |
|---|---|---|
| Data type | Discrete/categorical | Continuous/grouped |
| Gaps | Yes (between bars) | No (bars touch) |
| Unequal widths | Not applicable | Use frequency density |
Mean, Median, Mode
Quick Self-Check
- Mean of 2, 4, 6, 8, 10? (30/5 = 6)
- Median of 3, 1, 7, 5, 9? (Sorted: 1,3,5,7,9. Median = 5)
- Mode of 2, 3, 3, 5, 5, 5, 7? (5)