Let us again consider the grouped frequency distribution of the marks obtained by 60 students in Mathematics test.
|0 - 10||2|
|10 - 20||10|
|20 - 30||21|
|30 - 40||19|
|40 - 50||7|
|50 - 60||1|
This is displayed graphically as in the adjoining graph in following fig.
Observe that, here we have represented the groups of observations (i.e., class intervals) on the horizontal axis. The height of the bars show the frequency of the class-interval. Also, there is no gap between the bars as there is no gap between the class-intervals.
The graphical representation of data in this manner is called a histogram.
The following graph is another histogram in fig .
The shoppers who come to a departmental store are marked as: man (M), woman (W), boy (B) or girl (G). The following list gives the shoppers who came during the first hour in the morning
W W W G B W W M G G M M W W W W G B M W B G G M W W M M W W W M W B W G M W W W W G W M M W W M W G W M G W M M B G G W
Make a frequency distribution table using tally marks. Draw a bar graph to illustrate it.
Draw a histogram for the frequency table made for the data in Question 3 and answer the following questions.
(1) Which group has the maximum number of workers?
(2) How many workers earn Rs 850 and more?
(3) How many workers earn less than Rs 850?
For which of these would you use a histogram to show the data?
(a) The number of letters for different areas in a postman’s bag.
(b) The height of competitors in an athletics meet.
(c) The number of cassettes produced by 5 companies.
(d) The number of passengers boarding trains from 7:00 a.m. to 7:00 p.m. at a station.
Give reasons for each.
The weekly wages (in Rs) of 30 workers in a factory are.
830, 835, 890, 810, 835, 836, 869, 845, 898, 890, 820, 860, 832, 833, 855, 845, 804, 808, 812, 840, 885, 835, 835, 836, 878, 840, 868, 890, 806, 840
Using tally marks make a frequency table with intervals as 800 − 810, 810 − 820 and so on.
The number of hours for which students of a particular class watched television during holidays is shown through the given graph.
Answer the following
1) For how many hours did the maximum number of students watch TV?
2) How many students watched TV for less than 4 hours?
3) How many students spent more than 5 hours in watching TV?